diff --git a/flatten-openalex-jsonl.py b/flatten-openalex-jsonl.py
index b7a039b..d43f468 100644
--- a/flatten-openalex-jsonl.py
+++ b/flatten-openalex-jsonl.py
@@ -292,8 +292,12 @@ def flatten_authors():
                         author.get('display_name_alternatives'),
                         ensure_ascii=False)
                     author['last_known_institution'] = (
-                                author.get('last_known_institution') or {}).get(
-                        'id')
+                        (author.get('last_known_institutions')[0] 
+                         if isinstance(author.get('last_known_institutions'), list) 
+                         and author.get('last_known_institutions') 
+                         else author.get('last_known_institution')) or {}
+                    ).get('id')
+
                     authors_writer.writerow(author)
 
                     # ids