diff --git a/src/enums/MDNodaRepository.php b/src/enums/MDNodaRepository.php
index ffa81cd..c295cd1 100644
--- a/src/enums/MDNodaRepository.php
+++ b/src/enums/MDNodaRepository.php
@@ -277,7 +277,13 @@ enum MDNodaRepository implements MDValueEnumInterface, JsonSerializable {
             $id = strtr($id, $toRemove);
         }
 
-        if (preg_match("/^[0-9-X]*$/", $id) === false) return false;
+        // There is an issue with this regex
+        if (preg_match("/^[0-9-X]*$/", $id) === false) {
+            return false;
+        }
+        if (is_numeric(strtr($id, ['-' => '', 'X' => ''])) === false) {
+            return false;
+        }
 
         return $id;
 
@@ -375,7 +381,7 @@ enum MDNodaRepository implements MDValueEnumInterface, JsonSerializable {
             self::bnf       => self::validateNumericId($id, ["https://catalogue.bnf.fr/ark:/12148/cb"]),
             self::cona      => self::validateNumericId($id, ['https://vocab.getty.edu/page/cona/']),
             self::editionhumboldtdigital => self::validateGndId($id, ['https://edition-humboldt.de/register/personen/detail.xql?normid=http://d-nb.info/gnd/']),
-            self::gnd       => self::validateGndId($id, ['https://d-nb.info/gnd/']),
+            self::gnd       => self::validateGndId($id, ['http://d-nb.info/gnd/', 'https://d-nb.info/gnd/']),
             self::grobsystematik => self::validateNumericId($id, ['https://term.museum-digital.de/grobsystematik/tag/']),
             self::iconclass => self::validateIconclassId($id),
             self::lcsh      => self::validateLcshId($id),