diff --git a/thuthesis-author-year.bst b/thuthesis-author-year.bst
index 93540a2e..c89756de 100644
--- a/thuthesis-author-year.bst
+++ b/thuthesis-author-year.bst
@@ -1499,7 +1499,7 @@ FUNCTION {format.periodical.year.volume.number}
 
 FUNCTION {check.url}
 { url empty$ not
-    { "\url{" url * "}" * 'entry.url :=
+    { url 'entry.url :=
       #1 'entry.is.electronic :=
     }
     { howpublished empty$ not
@@ -1530,7 +1530,11 @@ FUNCTION {output.url}
 { show.url is.pure.electronic or
   entry.url empty$ not and
     { new.block
-      entry.url output
+      entry.url #1 #4 substring$ "\url{" =
+        { entry.url }
+        { "\url{" entry.url * "}" * }
+      if$
+      output
     }
     'skip$
   if$
@@ -1549,10 +1553,9 @@ FUNCTION {is.in.url}
     { #1 }
     { entry.url empty$
         { #0 }
-        { s "l" change.case$ 's :=
-          s text.length$ 'len :=
+        { s text.length$ 'len :=
           entry.url "l" change.case$ text.length$ 'charptr :=
-            { entry.url "l" change.case$ charptr len substring$ s = not
+            { entry.url "l" change.case$ charptr len substring$ s "l" change.case$ = not
               charptr #0 >
               and
             }
diff --git a/thuthesis-bachelor.bst b/thuthesis-bachelor.bst
index 7a3dd617..89621b54 100644
--- a/thuthesis-bachelor.bst
+++ b/thuthesis-bachelor.bst
@@ -1489,7 +1489,7 @@ FUNCTION {format.periodical.year.volume.number}
 
 FUNCTION {check.url}
 { url empty$ not
-    { "\url{" url * "}" * 'entry.url :=
+    { url 'entry.url :=
       #1 'entry.is.electronic :=
     }
     { howpublished empty$ not
@@ -1520,7 +1520,11 @@ FUNCTION {output.url}
 { show.url is.pure.electronic or
   entry.url empty$ not and
     { new.block
-      entry.url output
+      entry.url #1 #4 substring$ "\url{" =
+        { entry.url }
+        { "\url{" entry.url * "}" * }
+      if$
+      output
     }
     'skip$
   if$
@@ -1539,10 +1543,9 @@ FUNCTION {is.in.url}
     { #1 }
     { entry.url empty$
         { #0 }
-        { s "l" change.case$ 's :=
-          s text.length$ 'len :=
+        { s text.length$ 'len :=
           entry.url "l" change.case$ text.length$ 'charptr :=
-            { entry.url "l" change.case$ charptr len substring$ s = not
+            { entry.url "l" change.case$ charptr len substring$ s "l" change.case$ = not
               charptr #0 >
               and
             }
diff --git a/thuthesis-numeric.bst b/thuthesis-numeric.bst
index 81f7a5f3..83329640a 100644
--- a/thuthesis-numeric.bst
+++ b/thuthesis-numeric.bst
@@ -1489,7 +1489,7 @@ FUNCTION {format.periodical.year.volume.number}
 
 FUNCTION {check.url}
 { url empty$ not
-    { "\url{" url * "}" * 'entry.url :=
+    { url 'entry.url :=
       #1 'entry.is.electronic :=
     }
     { howpublished empty$ not
@@ -1520,7 +1520,11 @@ FUNCTION {output.url}
 { show.url is.pure.electronic or
   entry.url empty$ not and
     { new.block
-      entry.url output
+      entry.url #1 #4 substring$ "\url{" =
+        { entry.url }
+        { "\url{" entry.url * "}" * }
+      if$
+      output
     }
     'skip$
   if$
@@ -1539,10 +1543,9 @@ FUNCTION {is.in.url}
     { #1 }
     { entry.url empty$
         { #0 }
-        { s "l" change.case$ 's :=
-          s text.length$ 'len :=
+        { s text.length$ 'len :=
           entry.url "l" change.case$ text.length$ 'charptr :=
-            { entry.url "l" change.case$ charptr len substring$ s = not
+            { entry.url "l" change.case$ charptr len substring$ s "l" change.case$ = not
               charptr #0 >
               and
             }