diff --git a/application/src/Api/Representation/ItemRepresentation.php b/application/src/Api/Representation/ItemRepresentation.php
index b463639a8..e74d7dfba 100644
--- a/application/src/Api/Representation/ItemRepresentation.php
+++ b/application/src/Api/Representation/ItemRepresentation.php
@@ -104,7 +104,7 @@ public function primaryMedia()
 
     public function siteUrl($siteSlug = null, $canonical = false)
     {
-        if (!$siteSlug) {
+        if ($siteSlug === null) {
             $siteSlug = $this->getServiceLocator()->get('Application')
                 ->getMvcEvent()->getRouteMatch()->getParam('site-slug');
         }
diff --git a/application/src/Api/Representation/ItemSetRepresentation.php b/application/src/Api/Representation/ItemSetRepresentation.php
index d38826d70..2039e1e7d 100644
--- a/application/src/Api/Representation/ItemSetRepresentation.php
+++ b/application/src/Api/Representation/ItemSetRepresentation.php
@@ -73,7 +73,7 @@ public function primaryMedia()
 
     public function siteUrl($siteSlug = null, $canonical = false)
     {
-        if (!$siteSlug) {
+        if ($siteSlug === null) {
             $siteSlug = $this->getServiceLocator()->get('Application')
                 ->getMvcEvent()->getRouteMatch()->getParam('site-slug');
         }
diff --git a/application/src/Api/Representation/MediaRepresentation.php b/application/src/Api/Representation/MediaRepresentation.php
index c47280dbd..52fed9b58 100644
--- a/application/src/Api/Representation/MediaRepresentation.php
+++ b/application/src/Api/Representation/MediaRepresentation.php
@@ -314,7 +314,7 @@ public function displayTitle($default = null, $lang = null)
 
     public function siteUrl($siteSlug = null, $canonical = false)
     {
-        if (!$siteSlug) {
+        if ($siteSlug === null) {
             $siteSlug = $this->getServiceLocator()->get('Application')
                 ->getMvcEvent()->getRouteMatch()->getParam('site-slug');
         }
diff --git a/application/src/Api/Representation/SitePageRepresentation.php b/application/src/Api/Representation/SitePageRepresentation.php
index 0a4048af1..799d44469 100644
--- a/application/src/Api/Representation/SitePageRepresentation.php
+++ b/application/src/Api/Representation/SitePageRepresentation.php
@@ -139,7 +139,7 @@ public function modified()
 
     public function siteUrl($siteSlug = null, $canonical = false)
     {
-        if (!$siteSlug) {
+        if ($siteSlug === null) {
             $siteSlug = $this->site()->slug();
         }
         $url = $this->getViewHelper('Url');
diff --git a/application/src/Api/Representation/SiteRepresentation.php b/application/src/Api/Representation/SiteRepresentation.php
index 7d83c34e7..c46642888 100644
--- a/application/src/Api/Representation/SiteRepresentation.php
+++ b/application/src/Api/Representation/SiteRepresentation.php
@@ -257,7 +257,7 @@ public function owner()
 
     public function siteUrl($siteSlug = null, $canonical = false)
     {
-        if (!$siteSlug) {
+        if ($siteSlug === null) {
             $siteSlug = $this->slug();
         }
         $url = $this->getViewHelper('Url');