diff --git a/app/Http/Controllers/Oai/RequestController.php b/app/Http/Controllers/Oai/RequestController.php
index 6aef752..b2e50e5 100644
--- a/app/Http/Controllers/Oai/RequestController.php
+++ b/app/Http/Controllers/Oai/RequestController.php
@@ -378,10 +378,10 @@ class RequestController extends Controller
         $reldocIds = array();
 
         $metadataPrefix = null;
-        if (true === array_key_exists('metadataPrefix', $oaiRequest)) {
-            $metadataPrefix = $oaiRequest['metadataPrefix'];
-        }
-        $this->proc->setParameter('', 'oai_metadataPrefix', $metadataPrefix);
+        // if (true === array_key_exists('metadataPrefix', $oaiRequest)) {
+        //     $metadataPrefix = $oaiRequest['metadataPrefix'];
+        // }
+        // $this->proc->setParameter('', 'oai_metadataPrefix', $metadataPrefix);
 
         $tokenWorker = new ResumptionTokens();
         $tokenWorker->setResumptionPath($tokenTempPath);
@@ -405,6 +405,16 @@ class RequestController extends Controller
             // else no resumptionToken is given
         } else {
             // no resumptionToken is given
+            if (true === array_key_exists('metadataPrefix', $oaiRequest)) {
+                $metadataPrefix = $oaiRequest['metadataPrefix'];
+            } else {
+                throw new OaiModelException(
+                    'The prefix of the metadata argument is unknown.',
+                    OaiModelError::BADARGUMENT
+                );
+            }
+            $this->proc->setParameter('', 'oai_metadataPrefix', $metadataPrefix);
+
             $finder = Dataset::query();
             // add server state restrictions
             $finder->whereIn('server_state', $this->deliveringDocumentStates);
@@ -491,7 +501,6 @@ class RequestController extends Controller
                     );
                 }
             }
-
             
             $totalIds = $finder->count();
             $reldocIds = $finder->orderBy('publish_id')->pluck('publish_id')->toArray();
diff --git a/composer.lock b/composer.lock
index 46c45a5..2210070 100755
--- a/composer.lock
+++ b/composer.lock
@@ -746,16 +746,16 @@
         },
         {
             "name": "laravel/framework",
-            "version": "v6.18.26",
+            "version": "v6.18.31",
             "source": {
                 "type": "git",
                 "url": "https://github.com/laravel/framework.git",
-                "reference": "d11b6168c65251ffa81ae0dfaf017ad2f30013da"
+                "reference": "a731824421f9ebc586728ea9c7cff231a249aaa9"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/laravel/framework/zipball/d11b6168c65251ffa81ae0dfaf017ad2f30013da",
-                "reference": "d11b6168c65251ffa81ae0dfaf017ad2f30013da",
+                "url": "https://api.github.com/repos/laravel/framework/zipball/a731824421f9ebc586728ea9c7cff231a249aaa9",
+                "reference": "a731824421f9ebc586728ea9c7cff231a249aaa9",
                 "shasum": ""
             },
             "require": {
@@ -890,7 +890,7 @@
                 "framework",
                 "laravel"
             ],
-            "time": "2020-07-21T14:25:39+00:00"
+            "time": "2020-07-27T18:23:18+00:00"
         },
         {
             "name": "laravel/tinker",
@@ -1364,16 +1364,16 @@
         },
         {
             "name": "nesbot/carbon",
-            "version": "2.36.1",
+            "version": "2.37.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/briannesbitt/Carbon.git",
-                "reference": "ee7378a36cc62952100e718bcc58be4c7210e55f"
+                "reference": "1f61206de973d67f36ce50f041c792ddac663c3e"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/briannesbitt/Carbon/zipball/ee7378a36cc62952100e718bcc58be4c7210e55f",
-                "reference": "ee7378a36cc62952100e718bcc58be4c7210e55f",
+                "url": "https://api.github.com/repos/briannesbitt/Carbon/zipball/1f61206de973d67f36ce50f041c792ddac663c3e",
+                "reference": "1f61206de973d67f36ce50f041c792ddac663c3e",
                 "shasum": ""
             },
             "require": {
@@ -1449,7 +1449,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2020-07-04T12:29:56+00:00"
+            "time": "2020-07-28T06:04:54+00:00"
         },
         {
             "name": "nikic/php-parser",
diff --git a/public/docs/HandbuchTethys.pdf b/public/docs/HandbuchTethys.pdf
index adedb3d..e09c40f 100644
Binary files a/public/docs/HandbuchTethys.pdf and b/public/docs/HandbuchTethys.pdf differ