diff --git a/Classes/Domain/Model/PublishedItem.php b/Classes/Domain/Model/PublishedItem.php
index e8e3842..df77fb3 100755
--- a/Classes/Domain/Model/PublishedItem.php
+++ b/Classes/Domain/Model/PublishedItem.php
@@ -285,7 +285,7 @@ public function setMvdbId(): void
         $this->mvdbId = $this->publisher->getShorthand() .
             '_' . $minPlateId;
 
-        Collection::wrap($this->publishedSubitems)->
+        Collection::wrap($this->publishedSubitems->toArray())->
             each( function($subitem) { $this->setSubitemMvdbId($subitem); } );
     }
 
@@ -364,7 +364,7 @@ public function setInstrumentation($instrumentation): void
      * 
      * @return \Slub\MpdbCore\Domain\Model\Publisher $publisher
      */
-    public function getPublisher(): Publisher
+    public function getPublisher(): ?Publisher
     {
         return $this->publisher;
     }
@@ -699,7 +699,7 @@ public function isContainedWorksIdentified(): bool
      * 
      * @return string $responsiblePerson
      */
-    public function getResponsiblePerson(): GndPerson
+    public function getResponsiblePerson(): string
     {
         return $this->responsiblePerson;
     }
@@ -710,32 +710,11 @@ public function getResponsiblePerson(): GndPerson
      * @param string $responsiblePerson
      * @return void
      */
-    public function setResponsiblePerson(GndPerson $responsiblePerson): void
+    public function setResponsiblePerson(string $responsiblePerson): void
     {
         $this->responsiblePerson = $responsiblePerson;
     }
 
-    /**
-     * Returns the dateOfPublishing
-     * 
-     * @return \DateTime $dateOfPublishing
-     */
-    public function getDateOfPublishing(): \DateTime
-    {
-        return $this->dateOfPublishing;
-    }
-
-    /**
-     * Sets the dateOfPublishing
-     * 
-     * @param \DateTime $dateOfPublishing
-     * @return void
-     */
-    public function setDateOfPublishing(\DateTime $dateOfPublishing): void
-    {
-        $this->dateOfPublishing = $dateOfPublishing;
-    }
-
     /**
      * Returns the mvdbId
      * 
@@ -820,7 +799,7 @@ public function removeForm(Genre $formToRemove): void
      * 
      * @return \TYPO3\CMS\Extbase\Persistence\ObjectStorage<\Slub\DmOnt\Domain\Model\Genre> form
      */
-    public function getForm(): Genre
+    public function getGenre(): ObjectStorage
     {
         return $this->form;
     }
@@ -831,7 +810,7 @@ public function getForm(): Genre
      * @param \TYPO3\CMS\Extbase\Persistence\ObjectStorage<\Slub\DmOnt\Domain\Model\Genre> $form
      * @return void
      */
-    public function setForm(ObjectStorage $form): void
+    public function setGenre(ObjectStorage $form): void
     {
         $this->form = $form;
     }
@@ -892,10 +871,10 @@ public function getFinal(): int
     /**
      * Sets the final
      * 
-     * @param bool $final
+     * @param int $final
      * @return void
      */
-    public function setFinal(bool $final): void
+    public function setFinal(int $final): void
     {
         $this->final = $final;
         Collection::wrap($this->getContainedWorks()->toArray())->
@@ -1009,7 +988,7 @@ protected static function getWorkComposerName(GndWork $work): string
      */
     public function getPlateIds(): Collection
     {
-        return Collection::wrap($this->publishedSubitems)->
+        return Collection::wrap($this->publishedSubitems->toArray())->
             map( function($subitem) { return self::getSubitemPlateId($subitem); } );
     }
 
diff --git a/Tests/Unit/Domain/Model/PublishedItemTest.php b/Tests/Unit/Domain/Model/PublishedItemTest.php
new file mode 100755
index 0000000..154bad6
--- /dev/null
+++ b/Tests/Unit/Domain/Model/PublishedItemTest.php
@@ -0,0 +1,518 @@
+<?php
+namespace Slub\MpdbCore\Tests\Unit\Domain\Model;
+
+use Slub\DmNorm\Domain\Model\GndGenre;
+use Slub\DmNorm\Domain\Model\GndInstrument;
+use Slub\DmNorm\Domain\Model\GndPerson;
+use Slub\DmNorm\Domain\Model\GndWork;
+use Slub\MpdbCore\Domain\Model\Publisher;
+use Slub\MpdbCore\Domain\Model\PublishedItem;
+use Slub\MpdbCore\Domain\Model\PublishedSubitem;
+use TYPO3\CMS\Extbase\Persistence\ObjectStorage;
+use TYPO3\TestingFramework\Core\Unit\UnitTestCase;
+
+/**
+ * Test case.
+ *
+ * @author Matthias Richter <matthias.richter@slub-dresden.de>
+ */
+class PublishedItemTest extends UnitTestCase
+{
+    /**
+     * @var \SLUB\PublisherDb\Domain\Model\PublishedItem
+     */
+    protected $subject = null;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->subject = new PublishedItem();
+    }
+
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+    }
+
+    /**
+     * @test
+     */
+    public function getTitleReturnsInitialValueForString()
+    {
+        self::assertSame(
+            '',
+            $this->subject->getTitle()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setTitleForStringSetsTitle()
+    {
+        $this->subject->setTitle('Conceived at T3CON10');
+
+        self::assertSame(
+            'Conceived at T3CON10',
+            $this->subject->getTitle()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getTypeReturnsInitialValueForString()
+    {
+        self::assertSame(
+            '',
+            $this->subject->getType()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setTypeForStringSetsType()
+    {
+        $this->subject->setType('Conceived at T3CON10');
+
+        self::assertSame(
+            'Conceived at T3CON10',
+            $this->subject->getType()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getInstrumentationReturnsInitialValueForString()
+    {
+        self::assertSame(
+            '',
+            $this->subject->getInstrumentation()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setInstrumentationForStringSetsInstrumentation()
+    {
+        $this->subject->setInstrumentation('Conceived at T3CON10');
+
+        self::assertSame(
+            'Conceived at T3CON10',
+            $this->subject->getInstrumentation()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getDataAcquisitionCertainReturnsInitialValueForBool()
+    {
+        self::assertSame(
+            false,
+            $this->subject->getDataAcquisitionCertain()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setDataAcquisitionCertainForBoolSetsDataAcquisitionCertain()
+    {
+        $this->subject->setDataAcquisitionCertain(true);
+
+        self::assertSame(
+            true,
+            $this->subject->getDataAcquisitionCertain()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getRelatedPersonsKnownReturnsInitialValueForBool()
+    {
+        self::assertSame(
+            false,
+            $this->subject->getRelatedPersonsKnown()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setRelatedPersonsKnownForBoolSetsRelatedPersonsKnown()
+    {
+        $this->subject->setRelatedPersonsKnown(true);
+
+        self::assertSame(
+            true,
+            $this->subject->getRelatedPersonsKnown()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getWorkExaminedReturnsInitialValueForBool()
+    {
+        self::assertSame(
+            false,
+            $this->subject->getWorkExamined()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setWorkExaminedForBoolSetsWorkExamined()
+    {
+        $this->subject->setWorkExamined(true);
+
+        self::assertSame(
+            true,
+            $this->subject->getWorkExamined()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getDataSetManuallyCheckedReturnsInitialValueForBool()
+    {
+        self::assertSame(
+            false,
+            $this->subject->getDataSetManuallyChecked()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setDataSetManuallyCheckedForBoolSetsDataSetManuallyChecked()
+    {
+        $this->subject->setDataSetManuallyChecked(true);
+
+        self::assertSame(
+            true,
+            $this->subject->getDataSetManuallyChecked()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getContainedWorksIdentifiedReturnsInitialValueForBool()
+    {
+        self::assertSame(
+            false,
+            $this->subject->getContainedWorksIdentified()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setContainedWorksIdentifiedForBoolSetsContainedWorksIdentified()
+    {
+        $this->subject->setContainedWorksIdentified(true);
+
+        self::assertSame(
+            true,
+            $this->subject->getContainedWorksIdentified()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getResponsiblePersonReturnsInitialValueForString()
+    {
+        self::assertSame(
+            '',
+            $this->subject->getResponsiblePerson()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setResponsiblePersonForStringSetsResponsiblePerson()
+    {
+        $this->subject->setResponsiblePerson('Conceived at T3CON10');
+
+        self::assertSame(
+            'Conceived at T3CON10',
+            $this->subject->getResponsiblePerson()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getFinalReturnsInitialValueForInt()
+    {
+        self::assertSame(
+            0,
+            $this->subject->getFinal()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setFinalForIntSetsFinal()
+    {
+        $this->subject->setFinal(12);
+
+        self::assertSame(
+            12,
+            $this->subject->getFinal()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getLanguageReturnsInitialValueForString()
+    {
+        self::assertSame(
+            '',
+            $this->subject->getLanguage()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setLanguageForStringSetsLanguage()
+    {
+        $this->subject->setLanguage('Conceived at T3CON10');
+
+        self::assertSame(
+            'Conceived at T3CON10',
+            $this->subject->getLanguage()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getCommentReturnsInitialValueForString()
+    {
+        self::assertSame(
+            '',
+            $this->subject->getComment()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setCommentForStringSetsComment()
+    {
+        $this->subject->setComment('Conceived at T3CON10');
+
+        self::assertSame(
+            'Conceived at T3CON10',
+            $this->subject->getComment()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getContainedWorksReturnsInitialValueForWork()
+    {
+        $newObjectStorage = new ObjectStorage();
+        self::assertEquals(
+            $newObjectStorage,
+            $this->subject->getContainedWorks()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setContainedWorksForObjectStorageContainingWorkSetsContainedWorks()
+    {
+        $containedWork = new GndWork();
+        $objectStorageHoldingExactlyOneContainedWorks = new ObjectStorage();
+        $objectStorageHoldingExactlyOneContainedWorks->attach($containedWork);
+        $this->subject->setContainedWorks($objectStorageHoldingExactlyOneContainedWorks);
+
+        self::assertSame(
+            $objectStorageHoldingExactlyOneContainedWorks,
+            $this->subject->getContainedWorks()
+        );
+    }
+
+
+    /**
+     * @test
+     */
+    public function getEditorsReturnsInitialValueForPerson()
+    {
+        $newObjectStorage = new ObjectStorage();
+        self::assertEquals(
+            $newObjectStorage,
+            $this->subject->getEditors()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setEditorsForObjectStorageContainingPersonSetsEditors()
+    {
+        $editor = new GndPerson();
+        $objectStorageHoldingExactlyOneEditors = new ObjectStorage();
+        $objectStorageHoldingExactlyOneEditors->attach($editor);
+        $this->subject->setEditors($objectStorageHoldingExactlyOneEditors);
+
+        self::assertSame(
+            $objectStorageHoldingExactlyOneEditors,
+            $this->subject->getEditors()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getInstrumentsReturnsInitialValueForInstrument()
+    {
+        $newObjectStorage = new ObjectStorage();
+        self::assertEquals(
+            $newObjectStorage,
+            $this->subject->getInstruments()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setInstrumentsForObjectStorageContainingInstrumentSetsInstruments()
+    {
+        $instrument = new GndInstrument;
+        $objectStorageHoldingExactlyOneInstruments = new ObjectStorage();
+        $objectStorageHoldingExactlyOneInstruments->attach($instrument);
+        $this->subject->setInstruments($objectStorageHoldingExactlyOneInstruments);
+
+        self::assertSame(
+            $objectStorageHoldingExactlyOneInstruments,
+            $this->subject->getInstruments()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getGenreReturnsInitialValueForGenre()
+    {
+        $newObjectStorage = new ObjectStorage();
+        self::assertEquals(
+            $newObjectStorage,
+            $this->subject->getGenre()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setGenreForObjectStorageContainingGenreSetsForm()
+    {
+        $form = new GndGenre();
+        $objectStorageHoldingExactlyOneForm = new ObjectStorage();
+        $objectStorageHoldingExactlyOneForm->attach($form);
+        $this->subject->setGenre($objectStorageHoldingExactlyOneForm);
+
+        self::assertSame(
+            $objectStorageHoldingExactlyOneForm,
+            $this->subject->getGenre()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getFirstComposerReturnsInitialValueForPerson()
+    {
+        $newObjectStorage = new ObjectStorage();
+        self::assertEquals(
+            $newObjectStorage,
+            $this->subject->getFirstComposer()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setFirstComposerForObjectStorageContainingPersonSetsFirstComposer()
+    {
+        $firstComposer = new GndPerson();
+        $objectStorageHoldingExactlyOneFirstComposer = new ObjectStorage();
+        $objectStorageHoldingExactlyOneFirstComposer->attach($firstComposer);
+        $this->subject->setFirstComposer($objectStorageHoldingExactlyOneFirstComposer);
+
+        self::assertSame(
+            $objectStorageHoldingExactlyOneFirstComposer,
+            $this->subject->getFirstComposer()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getPublishedSubitemsReturnsInitialValueForPublishedSubitem()
+    {
+        $newObjectStorage = new ObjectStorage();
+        self::assertEquals(
+            $newObjectStorage,
+            $this->subject->getPublishedSubitems()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setPublishedSubitemsForObjectStorageContainingPublishedSubitemSetsPublishedSubitems()
+    {
+        $publishedSubitem = new PublishedSubitem();
+        $objectStorageHoldingExactlyOnePublishedSubitems = new ObjectStorage();
+        $objectStorageHoldingExactlyOnePublishedSubitems->attach($publishedSubitem);
+        $this->subject->setPublishedSubitems($objectStorageHoldingExactlyOnePublishedSubitems);
+
+        self::assertSame(
+            $objectStorageHoldingExactlyOnePublishedSubitems,
+            $this->subject->getPublishedSubitems()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function getPublisherReturnsInitialValueForPublisher()
+    {
+        self::assertEquals(
+            null,
+            $this->subject->getPublisher()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function setPublisherForPublisherSetsPublisher()
+    {
+        $publisherFixture = new Publisher();
+        $this->subject->setPublisher($publisherFixture);
+
+        self::assertSame(
+            $publisherFixture,
+            $this->subject->getPublisher()
+        );
+    }
+}
diff --git a/composer.json b/composer.json
index addaec8..73a53db 100755
--- a/composer.json
+++ b/composer.json
@@ -44,9 +44,11 @@
         "post-autoload-dump": [
             "TYPO3\\TestingFramework\\Composer\\ExtensionTestEnvironment::prepare"
         ],
-        "ci": [ "@ci:php" ],
+        "ci": [ "@ci:php", "@ci:tests" ],
         "ci:php": [ "@ci:php:stan" ],
-        "ci:php:stan": [ "phpstan analyse Classes" ]
+        "ci:php:stan": [ "phpstan analyse Classes" ],
+        "ci:tests": [ "@ci:tests:unit" ],
+        "ci:tests:unit": [ "phpunit -c config/UnitTests.xml" ]
     },
     "extra": {
         "typo3/cms": {
diff --git a/config/UnitTests.xml b/config/UnitTests.xml
new file mode 100644
index 0000000..a644f4f
--- /dev/null
+++ b/config/UnitTests.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.4/phpunit.xsd"
+         backupGlobals="true"
+         beStrictAboutTestsThatDoNotTestAnything="false"
+         bootstrap="../.Build/vendor/typo3/testing-framework/Resources/Core/Build/UnitTestsBootstrap.php"
+         cacheResult="false"
+         colors="true"
+         failOnRisky="true"
+         failOnWarning="true"
+         requireCoverageMetadata="true"
+>
+    <testsuites>
+        <testsuite name="MpdbCore">
+            <directory>../Tests/Unit</directory>
+        </testsuite>
+    </testsuites>
+
+    <source>
+        <include>
+            <directory>../Classes</directory>
+        </include>
+    </source>
+
+    <php>
+        <ini name="display_errors" value="1"/>
+        <env name="TYPO3_CONTEXT" value="Testing"/>
+    </php>
+</phpunit>