diff --git a/data/xml/references.xml b/data/xml/references.xml
index 8531c37..97c404e 100644
--- a/data/xml/references.xml
+++ b/data/xml/references.xml
@@ -259,14 +259,14 @@
 
 			<personDef index="83" name="Eina [Julie von Albedyll] " ref="http://d-nb.info/gnd/116275359"
 				vorname="Julie" nachname="von Albedyll" komm="albedyll" />
-			
+
 			<personDef index="84" name="Gerhard Friedrich Müller" ref="http://d-nb.info/gnd/118953362"
 				vorname="Gerhard Friedrich" nachname="Müller" komm="gf-müller" />
-			
-			<personDef index="85" name="Carl Heinrich Gottlob Lenz" 
+
+			<personDef index="85" name="Carl Heinrich Gottlob Lenz"
 				vorname="Carl Heinrich Gottlob" nachname="Lenz" komm="chg-lenz" />
-			
-			<personDef index="86" name="Unbekannter Freund" 
+
+			<personDef index="86" name="Unbekannter Freund"
 				vorname="NN" nachname="NN" komm="freund" />
 
 		</personDefs>
diff --git a/scripts/lint_verweise.py b/scripts/lint_verweise.py
index 4a1bde4..7099495 100644
--- a/scripts/lint_verweise.py
+++ b/scripts/lint_verweise.py
@@ -41,19 +41,19 @@ def get_person_def_ids(ref_root):
     If references.xml is un-namespaced, we can use a non-namespace XPath: //personDef
     Adjust if references.xml also has a namespace.
     """
-    return set(elem.get("index") for elem in ref_root.xpath("//personDef"))
+    return set(elem.get("index") for elem in ref_root.xpath("//lenz:personDef", namespaces=NAMESPACE_MAP))
 
 def get_location_def_ids(ref_root):
     """
     Retrieve all 'index' attributes from <locationDef index="..."> in references.xml.
     """
-    return set(elem.get("index") for elem in ref_root.xpath("//locationDef"))
+    return set(elem.get("index") for elem in ref_root.xpath("//lenz:locationDef", namespaces=NAMESPACE_MAP))
 
 def get_app_def_ids(ref_root):
     """
     Retrieve all 'index' attributes from <appDef index="..."> in references.xml.
     """
-    return set(elem.get("index") for elem in ref_root.xpath("//appDef"))
+    return set(elem.get("index") for elem in ref_root.xpath("//lenz:appDef", namespaces=NAMESPACE_MAP))
 
 def check_references(root, reference_data, filepath):
     """