diff --git a/src/sipcentric/__init__.py b/src/sipcentric/__init__.py
index fc6bcf0..3a6dcd7 100644
--- a/src/sipcentric/__init__.py
+++ b/src/sipcentric/__init__.py
@@ -230,51 +230,51 @@ class Customer(APIObject):
             return "/customers/"
 
     def endpoints(self):
-        for c in self._api.getMany(Endpoint.makeUrl(parent=self.url())):
+        for c in self._api.getMany(Endpoint.makeUrl(parent=self):
             yield Endpoint(self._api, data=c)
 
     def phonenumbers(self):
-        for c in self._api.getMany(PhoneNumber.makeUrl(parent=self.url())):
+        for c in self._api.getMany(PhoneNumber.makeUrl(parent=self):
             yield PhoneNumber(self._api, data=c)
 
     def calls(self, params=None):
-        for c in self._api.getMany(Call.makeUrl(parent=self.url()), params=params, pageSize=100):
+        for c in self._api.getMany(Call.makeUrl(parent=self, params=params, pageSize=100):
             yield Call(self._api, data=c)
 
     def callbundles(self):
-        for c in self._api.getMany(CallBundle.makeUrl(parent=self.url())):
+        for c in self._api.getMany(CallBundle.makeUrl(parent=self):
             yield CallBundle(self._api, data=c)
 
     def recordings(self):
-        for c in self._api.getMany(Recording.makeUrl(parent=self.url())):
+        for c in self._api.getMany(Recording.makeUrl(parent=self):
             yield Recording(self._api, data=c)
 
     def phonebooks(self):
-        for c in self._api.getMany(PhoneBook.makeUrl(parent=self.url())):
+        for c in self._api.getMany(PhoneBook.makeUrl(parent=self):
             yield PhoneBook(self._api, data=c)
 
     def timeintervals(self):
-        for c in self._api.getMany(TimeInterval.makeUrl(parent=self.url())):
+        for c in self._api.getMany(TimeInterval.makeUrl(parent=self):
             yield TimeInterval(self._api, data=c)
 
     def smss(self):
-        for c in self._api.getMany(Sms.makeUrl(parent=self.url())):
+        for c in self._api.getMany(Sms.makeUrl(parent=self):
             yield Sms(self._api, data=c)
 
     def sounds(self):
-        for c in self._api.getMany(Sound.makeUrl(parent=self.url())):
+        for c in self._api.getMany(Sound.makeUrl(parent=self):
             yield Sound(self._api, data=c)
 
     def outgoingcallerids(self):
-        for c in self._api.getMany(OutgoingCallerId.makeUrl(parent=self.url())):
+        for c in self._api.getMany(OutgoingCallerId.makeUrl(parent=self):
             yield OutgoingCallerId(self._api, data=c)
 
     def creditstatuses(self):
-        for c in self._api.getMany(CreditStatus.makeUrl(parent=self.url())):
+        for c in self._api.getMany(CreditStatus.makeUrl(parent=self):
             yield CreditStatus(self._api, data=c)
 
     def linkedusers(self):
-        for c in self._api.getMany(LinkedUser.makeUrl(parent=self.url())):
+        for c in self._api.getMany(LinkedUser.makeUrl(parent=self):
             yield LinkedUser(self._api, data=c)
 
     def create(self, parent=None, **kwargs):