diff -r b64c8c35c67d -r d2e6ee099125 server/src/app/Libraries/Sparql/GuzzleSparqlClient.php
--- a/server/src/app/Libraries/Sparql/GuzzleSparqlClient.php	Sat Jun 10 22:43:58 2017 +0200
+++ b/server/src/app/Libraries/Sparql/GuzzleSparqlClient.php	Mon Jun 12 14:53:59 2017 +0200
@@ -6,6 +6,7 @@
 use EasyRdf\Exception;
 use EasyRdf\Format;
 use EasyRdf\RdfNamespace;
+use GuzzleHttp\Client as GuzzleClient;
 
 /**
  * Wraps a Guzzle psr7 response into a EasyRdf\Http\Response interface
@@ -193,7 +194,7 @@
 
 class GuzzleSparqlClient extends Client {
 
-    public function __construct($httpClient, $queryUri, $updateUri = null) {
+    public function __construct(GuzzleClient $httpClient, $queryUri, $updateUri = null) {
         parent::__construct($queryUri, $updateUri);
         $this->httpClient = $httpClient;
     }