diff --git a/module/VuFind/src/VuFind/Resolver/Driver/AbstractBase.php b/module/VuFind/src/VuFind/Resolver/Driver/AbstractBase.php
index cdff08a703a7f8818b751ce39561c8b8383c2209..9119a8fd6d26631ec3ea4c53ce2deddbefc05103 100644
--- a/module/VuFind/src/VuFind/Resolver/Driver/AbstractBase.php
+++ b/module/VuFind/src/VuFind/Resolver/Driver/AbstractBase.php
@@ -68,7 +68,10 @@ abstract class AbstractBase implements DriverInterface
      */
     public function getResolverUrl($openURL)
     {
-        return $this->baseUrl . '?' . $openURL;
+        $url = $this->baseUrl;
+        $url .= strpos($url, '?') === false ? '?' : '&';
+        $url .= $openURL;
+        return $url;
     }
 
     /**
diff --git a/module/VuFind/src/VuFind/Resolver/Driver/Redi.php b/module/VuFind/src/VuFind/Resolver/Driver/Redi.php
index 6d4290d152500743375bef7ba781ae51ddae75a5..f240f5cbe41ef848dcba44e55a6f06f45e5a5fe4 100644
--- a/module/VuFind/src/VuFind/Resolver/Driver/Redi.php
+++ b/module/VuFind/src/VuFind/Resolver/Driver/Redi.php
@@ -81,7 +81,7 @@ class Redi extends AbstractBase
      */
     public function fetchLinks($openURL)
     {
-        $url = $this->baseUrl . '?' . $openURL;
+        $url = $this->getResolverUrl($openURL);
         $feed = $this->httpClient->setUri($url)->send()->getBody();
         return $feed;
     }
diff --git a/module/VuFind/src/VuFind/Resolver/Driver/Sfx.php b/module/VuFind/src/VuFind/Resolver/Driver/Sfx.php
index 8d89d6d8f3f86fb8de131e2649a9f430a59b22dd..c1995c9dd8d091a65d2c9bf9ddf41e654cc83561 100644
--- a/module/VuFind/src/VuFind/Resolver/Driver/Sfx.php
+++ b/module/VuFind/src/VuFind/Resolver/Driver/Sfx.php
@@ -72,8 +72,9 @@ class Sfx extends AbstractBase
     public function fetchLinks($openURL)
     {
         // Make the call to SFX and load results
-        $url = $this->baseUrl .
-            '?sfx.response_type=multi_obj_detailed_xml&svc.fulltext=yes&' . $openURL;
+        $url = $this->getResolverUrl(
+            'sfx.response_type=multi_obj_detailed_xml&svc.fulltext=yes&' . $openURL
+        );
         $feed = $this->httpClient->setUri($url)->send()->getBody();
         return $feed;
     }