diff --git a/scripts/codelists2ttl_sub-discipline.py b/scripts/codelists2ttl_sub-discipline.py
index 3317323..25a2850 100644
--- a/scripts/codelists2ttl_sub-discipline.py
+++ b/scripts/codelists2ttl_sub-discipline.py
@@ -174,8 +174,8 @@ def read_subdomain_index(index_file):
             fh2.write(ttl)
 
         concept_csv_dir = ROOTPATH / 'topic-hierarchy/earth-system-discipline'
-        concept_csv_file = f"{concept_csv_dir}/{row['Name']}" / "index.csv"
-        concept_ttl_file = register_ttl_dir / f"{row['Name']}.ttl"
+        concept_csv_file = f"{concept_csv_dir}/{row['Name']}/index.csv"
+        concept_ttl_file = f"{register_ttl_dir}/{row['Name']}.ttl"
 
         read_subdomain_index(concept_csv_file)