diff --git a/model/ConceptPropertyValueLiteral.php b/model/ConceptPropertyValueLiteral.php
index f22494c60..37edfe85f 100644
--- a/model/ConceptPropertyValueLiteral.php
+++ b/model/ConceptPropertyValueLiteral.php
@@ -44,8 +44,11 @@ public function getDatatype(): ?string
             return null;
         }
         $graph = $this->resource->getGraph();
-        $dtLabel = $graph->resource($datatype)->label($this->clang);
-        return $dtLabel->getValue();
+        if ($graph->resource($datatype)->label($this->clang)) {
+            $dtLabel = $graph->resource($datatype)->label($this->clang);
+            return $dtLabel->getValue();
+        }
+        return "";
     }
 
     public function getType()
diff --git a/tests/ConceptPropertyValueLiteralTest.php b/tests/ConceptPropertyValueLiteralTest.php
index 033090715..161605a07 100644
--- a/tests/ConceptPropertyValueLiteralTest.php
+++ b/tests/ConceptPropertyValueLiteralTest.php
@@ -73,29 +73,27 @@ public function testGetLabelForDatatype() {
     $this->assertEquals('NameOfTheDatatype', $propvals['665']->getDatatype());
   }
 
-    /**
-     * @covers ConceptPropertyValueLiteral::getLabel
-     */
-    public function testGetDatatypeWithoutLabel() {
-        $vocab = $this->model->getVocabulary('test');
-        $concepts = $vocab->getConceptInfo('http://www.skosmos.skos/test/ta112', 'en');
-        $props = $concepts[0]->getProperties();
-        $propvals = $props['skos:notation']->getValues();
-        $this->assertEquals('NameOfTheDatatype', $propvals['665']->getDatatype());
-    }
-
-
-    /**
-     * @covers ConceptPropertyValueLiteral::getLabel
-     */
-    public function testGetLabelForDatatypeIfNull() {
-        $vocab = $this->model->getVocabulary('test');
-        $concepts = $vocab->getConceptInfo('http://www.skosmos.skos/test/ta126', 'en');
-        $props = $concepts[0]->getProperties();
-        $propvals = $props['skos:notation']->getValues();
-        $this->assertNull($propvals['12.34']->getDatatype());
-    }
+  /**
+  * @covers ConceptPropertyValueLiteral::getLabel
+  */
+  public function testGetNotationDatatypeWithoutLabel() {
+    $vocab = $this->model->getVocabulary('test');
+    $concepts = $vocab->getConceptInfo('http://www.skosmos.skos/test/ta128', 'en');
+    $props = $concepts[0]->getProperties();
+    $propvals = $props['skos:notation']->getValues();
+    $this->assertEquals('', $propvals['testnotation']->getDatatype());
+  }
 
+/**
+ * @covers ConceptPropertyValueLiteral::getLabel
+ */
+public function testGetLabelForDatatypeIfNull() {
+    $vocab = $this->model->getVocabulary('test');
+    $concepts = $vocab->getConceptInfo('http://www.skosmos.skos/test/ta126', 'en');
+    $props = $concepts[0]->getProperties();
+    $propvals = $props['skos:notation']->getValues();
+    $this->assertNull($propvals['12.34']->getDatatype());
+}
 
   /**
    * @covers ConceptPropertyValueLiteral::getLang
diff --git a/tests/GenericSparqlTest.php b/tests/GenericSparqlTest.php
index 265eb2c5b..2edb74029 100644
--- a/tests/GenericSparqlTest.php
+++ b/tests/GenericSparqlTest.php
@@ -44,7 +44,7 @@ public function testGetGraph() {
    */
   public function testCountConcepts() {
     $actual = $this->sparql->countConcepts();
-    $this->assertEquals(17, $actual['http://www.w3.org/2004/02/skos/core#Concept']['count']);
+    $this->assertEquals(18, $actual['http://www.w3.org/2004/02/skos/core#Concept']['count']);
   }
 
   /**
diff --git a/tests/RestControllerTest.php b/tests/RestControllerTest.php
index a6c0c8e58..fb2cf7846 100644
--- a/tests/RestControllerTest.php
+++ b/tests/RestControllerTest.php
@@ -462,7 +462,7 @@ public function testVocabularyStatistics() {
   "concepts": {
     "class": "http://www.w3.org/2004/02/skos/core#Concept",
     "label": "Concept",
-    "count": 17,
+    "count": 18,
     "deprecatedCount": 1
   },
   "subTypes": [
diff --git a/tests/VocabularyTest.php b/tests/VocabularyTest.php
index 80d6820a0..425d45aa8 100644
--- a/tests/VocabularyTest.php
+++ b/tests/VocabularyTest.php
@@ -153,7 +153,7 @@ public function testGetLabelStatistics() {
   public function testGetStatistics() {
     $vocab = $this->model->getVocabulary('test');
     $stats = $vocab->getStatistics();
-    $this->assertEquals(17, $stats['http://www.w3.org/2004/02/skos/core#Concept']['count']);
+    $this->assertEquals(18, $stats['http://www.w3.org/2004/02/skos/core#Concept']['count']);
     $this->assertEquals(1, $stats['http://www.w3.org/2004/02/skos/core#Concept']['deprecatedCount']);
     $this->assertEquals(13, $stats['http://www.skosmos.skos/test-meta/TestClass']['count']);
     $this->assertEquals(1, $stats['http://www.skosmos.skos/test-meta/TestClass']['deprecatedCount']);
diff --git a/tests/test-vocab-data/test.ttl b/tests/test-vocab-data/test.ttl
index 9bc76fae8..3630c31b0 100644
--- a/tests/test-vocab-data/test.ttl
+++ b/tests/test-vocab-data/test.ttl
@@ -162,8 +162,8 @@ test:ta127
 
 test:ta128
   a mads:Geographic, skos:Concept ;
-  skos:notation "12.34"^^test:dt2 ;
-  skos:prefLabel "Europa"@nb .
+  skos:notation "testnotation"^^test:dt2 ;
+  skos:prefLabel "Europa2"@nb .
 
 test:ta1 a skos:Concept, meta:TestClass ;
     skos:inScheme test:conceptscheme ;