diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/ElectedResultMapper.java b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/ElectedResultMapper.java
index 91ae57a..85d075e 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/ElectedResultMapper.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/ElectedResultMapper.java
@@ -1,10 +1,12 @@
 package de.twomartens.wahlrecht.mapper.v1;
 
 import de.twomartens.wahlrecht.model.dto.v1.ElectedCandidate;
-import de.twomartens.wahlrecht.model.dto.v1.VotingResult;
+import de.twomartens.wahlrecht.model.dto.v1.NominationId;
 import de.twomartens.wahlrecht.model.internal.ElectedResult;
 import java.util.Collection;
 import java.util.Map;
+import java.util.Map.Entry;
+import java.util.stream.Collectors;
 import org.mapstruct.CollectionMappingStrategy;
 import org.mapstruct.Mapper;
 import org.mapstruct.NullValueCheckStrategy;
@@ -17,19 +19,19 @@ public interface ElectedResultMapper {
 
   de.twomartens.wahlrecht.model.dto.v1.ElectedResult mapToExternal(ElectedResult result);
 
-  Map<VotingResult, Collection<ElectedCandidate>> mapToExternal(
-      Map<de.twomartens.wahlrecht.model.internal.VotingResult,
+  Map<NominationId, Collection<ElectedCandidate>> mapToExternal(
+      Map<de.twomartens.wahlrecht.model.internal.NominationId,
           Collection<de.twomartens.wahlrecht.model.internal.ElectedCandidate>> value);
 
   Collection<ElectedCandidate> mapToExternal(
       Collection<de.twomartens.wahlrecht.model.internal.ElectedCandidate> value);
 
-  ElectedResult mapToInternal(de.twomartens.wahlrecht.model.dto.v1.ElectedResult result);
+  default Map<de.twomartens.wahlrecht.model.internal.NominationId,
+      Collection<de.twomartens.wahlrecht.model.internal.ElectedCandidate>> map(
+      Map<de.twomartens.wahlrecht.model.internal.VotingResult,
+          Collection<de.twomartens.wahlrecht.model.internal.ElectedCandidate>> value) {
+    return value.entrySet().stream()
+        .collect(Collectors.toMap(entry -> entry.getKey().getNominationId(), Entry::getValue));
+  }
 
-  Map<de.twomartens.wahlrecht.model.internal.VotingResult,
-      Collection<de.twomartens.wahlrecht.model.internal.ElectedCandidate>> mapToInternal(
-      Map<VotingResult, Collection<ElectedCandidate>> value);
-
-  Collection<de.twomartens.wahlrecht.model.internal.ElectedCandidate> mapToInternal(
-      Collection<ElectedCandidate> value);
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/NominationIdMapper.java b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/NominationIdMapper.java
new file mode 100644
index 0000000..5d26c5b
--- /dev/null
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/NominationIdMapper.java
@@ -0,0 +1,14 @@
+package de.twomartens.wahlrecht.mapper.v1;
+
+import de.twomartens.wahlrecht.model.dto.v1.NominationId;
+import org.mapstruct.CollectionMappingStrategy;
+import org.mapstruct.Mapper;
+import org.mapstruct.NullValueCheckStrategy;
+import org.mapstruct.ReportingPolicy;
+
+@Mapper(collectionMappingStrategy = CollectionMappingStrategy.ADDER_PREFERRED,
+    nullValueCheckStrategy = NullValueCheckStrategy.ALWAYS,
+    unmappedTargetPolicy = ReportingPolicy.IGNORE)
+public interface NominationIdMapper {
+  NominationId mapToExternal(de.twomartens.wahlrecht.model.internal.NominationId id);
+}
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/NominationMapper.java b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/NominationMapper.java
index f8a168a..8b60d1c 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/NominationMapper.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/NominationMapper.java
@@ -2,6 +2,7 @@ package de.twomartens.wahlrecht.mapper.v1;
 
 import de.twomartens.wahlrecht.model.db.Nomination;
 import de.twomartens.wahlrecht.model.internal.Candidate;
+import de.twomartens.wahlrecht.model.internal.NominationId;
 import java.util.Collection;
 import org.mapstruct.CollectionMappingStrategy;
 import org.mapstruct.Mapper;
@@ -16,15 +17,35 @@ public interface NominationMapper {
 
   de.twomartens.wahlrecht.model.dto.v1.Nomination mapToExternal(Nomination nomination);
 
-  de.twomartens.wahlrecht.model.internal.Nomination mapToInternal(
-      de.twomartens.wahlrecht.model.dto.v1.Nomination nomination);
+  default de.twomartens.wahlrecht.model.internal.Nomination mapToInternal(
+      de.twomartens.wahlrecht.model.dto.v1.Nomination nomination) {
+    de.twomartens.wahlrecht.model.internal.Nomination result =
+        new de.twomartens.wahlrecht.model.internal.Nomination(
+            new NominationId(nomination.getElectionName(), nomination.getPartyAbbreviation(),
+                nomination.getName()),
+            nomination.isSupportVotesOnNomination()
+        );
+    result.addCandidates(mapFromDto(nomination.getCandidates()));
+    return result;
+  }
 
-  de.twomartens.wahlrecht.model.internal.Nomination mapToInternal(Nomination nomination);
+  default de.twomartens.wahlrecht.model.internal.Nomination mapToInternal(Nomination nomination) {
+    de.twomartens.wahlrecht.model.internal.Nomination result =
+        new de.twomartens.wahlrecht.model.internal.Nomination(
+            new NominationId(nomination.getElectionName(), nomination.getPartyAbbreviation(),
+                nomination.getName()),
+            nomination.isSupportVotesOnNomination()
+        );
+    result.addCandidates(mapFromDb(nomination.getCandidates()));
+    return result;
+  }
 
   @Mapping(target = "id", ignore = true)
   @Mapping(target = "created", ignore = true)
   @Mapping(target = "lastModified", ignore = true)
   Nomination mapToDB(de.twomartens.wahlrecht.model.dto.v1.Nomination nomination);
 
-  Collection<Candidate> map(Collection<de.twomartens.wahlrecht.model.db.Candidate> candidates);
+  Collection<Candidate> mapFromDb(Collection<de.twomartens.wahlrecht.model.db.Candidate> candidates);
+
+  Collection<Candidate> mapFromDto(Collection<de.twomartens.wahlrecht.model.dto.v1.Candidate> candidates);
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/VotingResultMapper.java b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/VotingResultMapper.java
index e6c70a4..2c0d4a9 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/VotingResultMapper.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/mapper/v1/VotingResultMapper.java
@@ -1,5 +1,6 @@
 package de.twomartens.wahlrecht.mapper.v1;
 
+import de.twomartens.wahlrecht.model.internal.NominationId;
 import de.twomartens.wahlrecht.model.internal.VotingResult;
 import org.mapstruct.CollectionMappingStrategy;
 import org.mapstruct.Mapper;
@@ -11,7 +12,24 @@ import org.mapstruct.ReportingPolicy;
     unmappedTargetPolicy = ReportingPolicy.IGNORE)
 public interface VotingResultMapper {
 
-  de.twomartens.wahlrecht.model.dto.v1.VotingResult mapToExternal(VotingResult result);
+  default de.twomartens.wahlrecht.model.dto.v1.VotingResult mapToExternal(VotingResult result) {
+    return new de.twomartens.wahlrecht.model.dto.v1.VotingResult(
+        result.getNominationId().electionName(),
+        result.getNominationId().partyAbbreviation(),
+        result.getNominationId().name(),
+        result.getVotesOnNomination(),
+        result.getVotesThroughHealing(),
+        result.getVotesPerPosition()
+    );
+  }
 
-  VotingResult mapToInternal(de.twomartens.wahlrecht.model.dto.v1.VotingResult result);
+  default VotingResult mapToInternal(de.twomartens.wahlrecht.model.dto.v1.VotingResult result) {
+    return new VotingResult(
+        new NominationId(result.electionName(), result.partyAbbreviation(),
+            result.nominationName()),
+        result.votesOnNomination(),
+        result.votesThroughHealing(),
+        result.votesPerPosition()
+    );
+  }
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/ElectedResult.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/ElectedResult.java
index 41fa17e..4aad250 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/ElectedResult.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/ElectedResult.java
@@ -1,12 +1,13 @@
 package de.twomartens.wahlrecht.model.dto.v1;
 
+import de.twomartens.wahlrecht.model.internal.NominationId;
 import java.util.Collection;
 import java.util.LinkedList;
 import java.util.Map;
 import lombok.Builder;
 
 @Builder
-public record ElectedResult(Map<VotingResult, Collection<ElectedCandidate>> electedCandidates,
+public record ElectedResult(Map<NominationId, Collection<ElectedCandidate>> electedCandidates,
                             LinkedList<Double> usedElectionNumbers) {
 
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/NominationId.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/NominationId.java
new file mode 100644
index 0000000..6eadcfb
--- /dev/null
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/NominationId.java
@@ -0,0 +1,5 @@
+package de.twomartens.wahlrecht.model.dto.v1;
+
+public record NominationId(String electionName, String partyAbbreviation, String name) {
+
+}
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/PartyInElection.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/PartyInElection.java
index e81e547..4c4f707 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/PartyInElection.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/PartyInElection.java
@@ -17,11 +17,12 @@ import org.springframework.lang.NonNull;
 @ToString(onlyExplicitlyIncluded = true)
 @FieldDefaults(level = AccessLevel.PRIVATE)
 public class PartyInElection {
-    String electionName;
-    @Include
-    String abbreviation;
-    String name;
-    Nomination overallNomination;
-    @NonNull
-    Map<Integer, Nomination> constituencyNominations = new HashMap<>();
+
+  String electionName;
+  @Include
+  String abbreviation;
+  String name;
+  Nomination overallNomination;
+  @NonNull
+  Map<Integer, Nomination> constituencyNominations = new HashMap<>();
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/VotingResult.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/VotingResult.java
index 4bdeda4..1958e78 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/VotingResult.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/dto/v1/VotingResult.java
@@ -2,7 +2,8 @@ package de.twomartens.wahlrecht.model.dto.v1;
 
 import java.util.Map;
 
-public record VotingResult(int votesOnNomination, int votesThroughHealing, Integer totalVotes,
-                           Map<Integer, Integer> votesPerPosition, String nominationName) {
+public record VotingResult(String electionName, String partyAbbreviation, String nominationName,
+                           int votesOnNomination, int votesThroughHealing,
+                           Map<Integer, Integer> votesPerPosition) {
 
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/ElectedResult.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/ElectedResult.java
index 1ba7ccc..9da5976 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/ElectedResult.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/ElectedResult.java
@@ -11,9 +11,9 @@ import lombok.Builder;
 public record ElectedResult(Map<VotingResult, Collection<ElectedCandidate>> electedCandidates,
                             LinkedList<Double> usedElectionNumbers) {
 
-  public Map<Nomination, Collection<ElectedCandidate>> electedCandidatesByNomination() {
+  public Map<NominationId, Collection<ElectedCandidate>> electedCandidatesByNomination() {
     return electedCandidates.entrySet().stream()
-        .collect(Collectors.toMap(entry -> entry.getKey().getNomination(), Entry::getValue));
+        .collect(Collectors.toMap(entry -> entry.getKey().getNominationId(), Entry::getValue));
   }
 
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/Nomination.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/Nomination.java
index b454d4a..4a16da1 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/Nomination.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/Nomination.java
@@ -6,18 +6,13 @@ import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import lombok.Getter;
 import lombok.RequiredArgsConstructor;
-import lombok.ToString;
-import lombok.ToString.Include;
 
 @RequiredArgsConstructor
-@ToString(onlyExplicitlyIncluded = true)
 public class Nomination {
-
-  private final String electionName;
-  private final String partyAbbreviation;
-  @Include
-  private final String name;
+  @Getter
+  private final NominationId id;
   private final boolean supportVotesOnNomination;
   private final List<Candidate> candidates = new ArrayList<>();
   private final Map<Candidate, Integer> candidateToPosition = new HashMap<>();
@@ -52,4 +47,9 @@ public class Nomination {
   public boolean supportsVotesOnNomination() {
     return supportVotesOnNomination;
   }
+
+  @Override
+  public String toString() {
+    return id.name();
+  }
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/SeatResult.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/SeatResult.java
index ca95cbe..f077981 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/SeatResult.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/SeatResult.java
@@ -10,8 +10,8 @@ import lombok.Builder;
 public record SeatResult(Map<VotingResult, Integer> seatsPerResult,
                          LinkedList<Double> usedElectionNumbers) {
 
-  public Map<Nomination, Integer> seatsPerNomination() {
+  public Map<NominationId, Integer> seatsPerNomination() {
     return seatsPerResult.entrySet().stream()
-        .collect(Collectors.toMap(entry -> entry.getKey().getNomination(), Entry::getValue));
+        .collect(Collectors.toMap(entry -> entry.getKey().getNominationId(), Entry::getValue));
   }
 }
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/VotingResult.java b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/VotingResult.java
index 28ea5f7..d3599cd 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/VotingResult.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/model/internal/VotingResult.java
@@ -7,19 +7,19 @@ import lombok.Getter;
 @Getter
 public class VotingResult {
 
+  private final NominationId nominationId;
   private final int votesOnNomination;
   private final int votesThroughHealing;
   private final Map<Integer, Integer> votesPerPosition;
-  private final Nomination nomination;
   private Integer totalVotes = null;
 
   @Builder
-  public VotingResult(int votesOnNomination, int votesThroughHealing,
-      Map<Integer, Integer> votesPerPosition, Nomination nomination) {
+  public VotingResult(NominationId nominationId, int votesOnNomination, int votesThroughHealing,
+      Map<Integer, Integer> votesPerPosition) {
     this.votesOnNomination = votesOnNomination;
     this.votesThroughHealing = votesThroughHealing;
     this.votesPerPosition = votesPerPosition;
-    this.nomination = nomination;
+    this.nominationId = nominationId;
   }
 
   public int getTotalVotes() {
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/service/CalculationService.java b/module-server/src/main/java/de/twomartens/wahlrecht/service/CalculationService.java
index 0b42393..f59a407 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/service/CalculationService.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/service/CalculationService.java
@@ -7,6 +7,7 @@ import de.twomartens.wahlrecht.model.internal.ElectedCandidate;
 import de.twomartens.wahlrecht.model.internal.ElectedResult;
 import de.twomartens.wahlrecht.model.internal.Election;
 import de.twomartens.wahlrecht.model.internal.Nomination;
+import de.twomartens.wahlrecht.model.internal.NominationId;
 import de.twomartens.wahlrecht.model.internal.SeatResult;
 import de.twomartens.wahlrecht.model.internal.VotingResult;
 import java.util.ArrayList;
@@ -20,14 +21,20 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.function.Function;
 import java.util.stream.Collectors;
+import lombok.RequiredArgsConstructor;
 import org.springframework.lang.NonNull;
 import org.springframework.stereotype.Service;
 
+@RequiredArgsConstructor
 @Service
 public class CalculationService {
 
+  private final NominationService nominationService;
+
   private final LinkedList<Double> electionNumberHistory = new LinkedList<>();
 
+
+
   public ElectedResult calculateConstituency(@NonNull Constituency constituency,
       @NonNull Collection<VotingResult> votingResults) {
     electionNumberHistory.clear();
@@ -127,7 +134,8 @@ public class CalculationService {
     Map<Candidate, ElectedCandidate> electedCandidateMap = alreadyElectedCandidates.stream()
         .collect(Collectors.toMap(ElectedCandidate::candidate, Function.identity()));
 
-    Nomination nomination = votingResult.getNomination();
+    NominationId nominationId = votingResult.getNominationId();
+    Nomination nomination = nominationService.getNominationInternal(nominationId);
     if (nomination.supportsVotesOnNomination()) {
       int seatsByNomination = calculateSeatsByNominationOrder(votingResult, numberOfSeats);
       seatsByVoteOrder = numberOfSeats - seatsByNomination;
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/service/NominationService.java b/module-server/src/main/java/de/twomartens/wahlrecht/service/NominationService.java
index d0b6945..67d1d66 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/service/NominationService.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/service/NominationService.java
@@ -1,5 +1,6 @@
 package de.twomartens.wahlrecht.service;
 
+import de.twomartens.wahlrecht.mapper.v1.NominationMapper;
 import de.twomartens.wahlrecht.model.db.Candidate;
 import de.twomartens.wahlrecht.model.db.Nomination;
 import de.twomartens.wahlrecht.model.internal.NominationId;
@@ -10,16 +11,29 @@ import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import lombok.RequiredArgsConstructor;
+import org.mapstruct.factory.Mappers;
 import org.springframework.stereotype.Service;
 
 @RequiredArgsConstructor
 @Service
 public class NominationService {
 
+  private final NominationMapper mapper = Mappers.getMapper(NominationMapper.class);
   private final NominationRepository repository;
   private final CandidateService candidateService;
   private Map<NominationId, Nomination> nominations;
 
+  public Nomination getNomination(NominationId id) {
+    if (nominations == null) {
+      fetchNominations();
+    }
+    return nominations.get(id);
+  }
+
+  public de.twomartens.wahlrecht.model.internal.Nomination getNominationInternal(NominationId id) {
+    return mapper.mapToInternal(getNomination(id));
+  }
+
   public Nomination storeNomination(Nomination nomination) {
     if (nomination == null) {
       return null;
diff --git a/module-server/src/main/java/de/twomartens/wahlrecht/service/PartyService.java b/module-server/src/main/java/de/twomartens/wahlrecht/service/PartyService.java
index b8bdbc5..9381bec 100644
--- a/module-server/src/main/java/de/twomartens/wahlrecht/service/PartyService.java
+++ b/module-server/src/main/java/de/twomartens/wahlrecht/service/PartyService.java
@@ -39,7 +39,7 @@ public class PartyService {
         abbreviation, electionName);
     if (optionalParty.isEmpty()) {
       throw new ResponseStatusException(HttpStatus.NOT_FOUND,
-          "no party found for %s and %s" .formatted(electionName, abbreviation));
+          "no party found for %s and %s".formatted(electionName, abbreviation));
     }
     return optionalParty.get();
   }
diff --git a/module-server/src/test/java/de/twomartens/wahlrecht/service/CalculationServiceTest.java b/module-server/src/test/java/de/twomartens/wahlrecht/service/CalculationServiceTest.java
index 894d708..2106a4c 100644
--- a/module-server/src/test/java/de/twomartens/wahlrecht/service/CalculationServiceTest.java
+++ b/module-server/src/test/java/de/twomartens/wahlrecht/service/CalculationServiceTest.java
@@ -1,5 +1,7 @@
 package de.twomartens.wahlrecht.service;
 
+import static org.mockito.Mockito.when;
+
 import de.twomartens.wahlrecht.model.internal.Candidate;
 import de.twomartens.wahlrecht.model.internal.Constituency;
 import de.twomartens.wahlrecht.model.internal.Elected;
@@ -7,6 +9,7 @@ import de.twomartens.wahlrecht.model.internal.ElectedCandidate;
 import de.twomartens.wahlrecht.model.internal.ElectedResult;
 import de.twomartens.wahlrecht.model.internal.Election;
 import de.twomartens.wahlrecht.model.internal.Nomination;
+import de.twomartens.wahlrecht.model.internal.NominationId;
 import de.twomartens.wahlrecht.model.internal.SeatResult;
 import de.twomartens.wahlrecht.model.internal.VotingResult;
 import de.twomartens.wahlrecht.model.internal.VotingThreshold;
@@ -23,8 +26,12 @@ import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
 import org.springframework.lang.NonNull;
 
+@ExtendWith(MockitoExtension.class)
 class CalculationServiceTest {
 
   private static final String BEZIRKSWAHL = "Bezirkswahl 2019";
@@ -106,6 +113,9 @@ class CalculationServiceTest {
       871, 1907, 987);
   private CalculationService service;
 
+  @Mock
+  private NominationService nominationService;
+
   @BeforeAll
   static void setUp() {
     setUpCandidatesConstituency();
@@ -152,7 +162,7 @@ class CalculationServiceTest {
         .votesThroughHealing(votesThroughHealing)
         .votesOnNomination(votesOnNomination)
         .votesPerPosition(buildVotesPerPosition(votes))
-        .nomination(nomination)
+        .nominationId(nomination.getId())
         .build();
   }
 
@@ -223,7 +233,8 @@ class CalculationServiceTest {
 
   private static Nomination buildNomination(String partyAbbreviation,
       String name, boolean supportVotesOnNomination) {
-    return new Nomination(BEZIRKSWAHL, partyAbbreviation, name, supportVotesOnNomination);
+    return new Nomination(new NominationId(BEZIRKSWAHL, partyAbbreviation, name),
+        supportVotesOnNomination);
   }
 
   private static Collection<Candidate> buildCandidates(String... names) {
@@ -239,7 +250,7 @@ class CalculationServiceTest {
 
   @BeforeEach
   void setService() {
-    service = new CalculationService();
+    service = new CalculationService(nominationService);
   }
 
   @Test
@@ -252,16 +263,18 @@ class CalculationServiceTest {
         FDP_NIENDORF_RESULT,
         AFD_NIENDORF_RESULT
     );
-
+    when(nominationService.getNominationInternal(SPD_NIENDORF.getId())).thenReturn(SPD_NIENDORF);
+    when(nominationService.getNominationInternal(CDU_NIENDORF.getId())).thenReturn(CDU_NIENDORF);
+    when(nominationService.getNominationInternal(GRUENE_NIENDORF.getId())).thenReturn(GRUENE_NIENDORF);
     ElectedResult elected = service.calculateConstituency(NIENDORF, votingResults);
 
     Assertions.assertThat(elected.electedCandidatesByNomination())
-        .containsKey(SPD_NIENDORF)
-        .containsKey(CDU_NIENDORF)
-        .containsKey(GRUENE_NIENDORF)
-        .doesNotContainKey(LINKE_NIENDORF)
-        .doesNotContainKey(AFD_NIENDORF)
-        .doesNotContainKey(FDP_NIENDORF);
+        .containsKey(SPD_NIENDORF.getId())
+        .containsKey(CDU_NIENDORF.getId())
+        .containsKey(GRUENE_NIENDORF.getId())
+        .doesNotContainKey(LINKE_NIENDORF.getId())
+        .doesNotContainKey(AFD_NIENDORF.getId())
+        .doesNotContainKey(FDP_NIENDORF.getId());
   }
 
   @Test
@@ -285,12 +298,12 @@ class CalculationServiceTest {
     SeatResult result = service.calculateOverallSeatDistribution(election, votingResults);
 
     Assertions.assertThat(result.seatsPerNomination())
-        .containsEntry(SPD_BEZIRK, 12)
-        .containsEntry(CDU_BEZIRK, 9)
-        .containsEntry(LINKE_BEZIRK, 5)
-        .containsEntry(FDP_BEZIRK, 3)
-        .containsEntry(GRUENE_BEZIRK, 19)
-        .containsEntry(AFD_BEZIRK, 3);
+        .containsEntry(SPD_BEZIRK.getId(), 12)
+        .containsEntry(CDU_BEZIRK.getId(), 9)
+        .containsEntry(LINKE_BEZIRK.getId(), 5)
+        .containsEntry(FDP_BEZIRK.getId(), 3)
+        .containsEntry(GRUENE_BEZIRK.getId(), 19)
+        .containsEntry(AFD_BEZIRK.getId(), 3);
   }
 
   @Test
@@ -304,29 +317,35 @@ class CalculationServiceTest {
         AFD_BEZIRK_RESULT, 3
     );
     Map<VotingResult, Collection<ElectedCandidate>> electedCandidates = setUpConstituencyResults();
+    when(nominationService.getNominationInternal(SPD_BEZIRK.getId())).thenReturn(SPD_BEZIRK);
+    when(nominationService.getNominationInternal(CDU_BEZIRK.getId())).thenReturn(CDU_BEZIRK);
+    when(nominationService.getNominationInternal(FDP_BEZIRK.getId())).thenReturn(FDP_BEZIRK);
+    when(nominationService.getNominationInternal(GRUENE_BEZIRK.getId())).thenReturn(GRUENE_BEZIRK);
+    when(nominationService.getNominationInternal(LINKE_BEZIRK.getId())).thenReturn(LINKE_BEZIRK);
+    when(nominationService.getNominationInternal(AFD_BEZIRK.getId())).thenReturn(AFD_BEZIRK);
 
     ElectedResult result = service.calculateElectedOverallCandidates(seatsPerVotingResult,
         electedCandidates);
 
     Assertions.assertThat(result.electedCandidatesByNomination())
-        .anySatisfy((nomination, candidates) -> {
-          Assertions.assertThat(nomination).isEqualTo(SPD_BEZIRK);
+        .anySatisfy((id, candidates) -> {
+          Assertions.assertThat(id).isEqualTo(SPD_BEZIRK.getId());
           Assertions.assertThat(candidates)
               .anyMatch(candidate -> candidate.name().equals(GOTTLIEB_GABOR)
                   && candidate.elected() == Elected.OVERALL_NOMINATION_ORDER)
               .anyMatch(candidate -> candidate.name().equals(RIEGEL_ANN_KATHRIN)
                   && candidate.elected() == Elected.OVERALL_VOTE_ORDER);
         })
-        .anySatisfy((nomination, candidates) -> {
-          Assertions.assertThat(nomination).isEqualTo(CDU_BEZIRK);
+        .anySatisfy((id, candidates) -> {
+          Assertions.assertThat(id).isEqualTo(CDU_BEZIRK.getId());
           Assertions.assertThat(candidates)
               .anyMatch(candidate -> candidate.name().equals(HOEFLICH_JUTTA)
                   && candidate.elected() == Elected.OVERALL_NOMINATION_ORDER)
               .anyMatch(candidate -> candidate.name().equals(DR_LANGHEIN_A_W_HEINRICH)
                   && candidate.elected() == Elected.OVERALL_VOTE_ORDER);
         })
-        .anySatisfy((nomination, candidates) -> {
-          Assertions.assertThat(nomination).isEqualTo(LINKE_BEZIRK);
+        .anySatisfy((id, candidates) -> {
+          Assertions.assertThat(id).isEqualTo(LINKE_BEZIRK.getId());
           Assertions.assertThat(candidates)
               .anyMatch(candidate -> candidate.name().equals(PAGELS_MANUELA)
                   && candidate.elected() == Elected.OVERALL_NOMINATION_ORDER)
@@ -335,8 +354,8 @@ class CalculationServiceTest {
               .anyMatch(candidate -> candidate.name().equals(KLEINERT_MIKEY)
                   && candidate.elected() == Elected.OVERALL_VOTE_ORDER);
         })
-        .anySatisfy((nomination, candidates) -> {
-          Assertions.assertThat(nomination).isEqualTo(FDP_BEZIRK);
+        .anySatisfy((id, candidates) -> {
+          Assertions.assertThat(id).isEqualTo(FDP_BEZIRK.getId());
           Assertions.assertThat(candidates)
               .anyMatch(candidate -> candidate.name().equals(KRUEGER_KLAUS)
                   && candidate.elected() == Elected.OVERALL_NOMINATION_ORDER)
@@ -345,8 +364,8 @@ class CalculationServiceTest {
               .anyMatch(candidate -> candidate.name().equals(MUELLER_SOENKSEN_BURKHARDT)
                   && candidate.elected() == Elected.OVERALL_VOTE_ORDER);
         })
-        .anySatisfy((nomination, candidates) -> {
-          Assertions.assertThat(nomination).isEqualTo(AFD_BEZIRK);
+        .anySatisfy((id, candidates) -> {
+          Assertions.assertThat(id).isEqualTo(AFD_BEZIRK.getId());
           Assertions.assertThat(candidates)
               .anyMatch(candidate -> candidate.name().equals(SCHOEMER_DIRK)
                   && candidate.elected() == Elected.OVERALL_NOMINATION_ORDER)
@@ -355,8 +374,8 @@ class CalculationServiceTest {
               .anyMatch(candidate -> candidate.name().equals(PILLATZKE_JOERG)
                   && candidate.elected() == Elected.OVERALL_VOTE_ORDER);
         })
-        .anySatisfy((nomination, candidates) -> {
-          Assertions.assertThat(nomination).isEqualTo(GRUENE_BEZIRK);
+        .anySatisfy((id, candidates) -> {
+          Assertions.assertThat(id).isEqualTo(GRUENE_BEZIRK.getId());
           Assertions.assertThat(candidates)
               .anyMatch(candidate -> candidate.name().equals(KUHLMANN_DIETMAR)
                   && candidate.elected() == Elected.OVERALL_NOMINATION_ORDER)