Update app.py

app.py

@@ -90,6 +90,7 @@ def create_bibtex_entry(data):
     
     if match_year:
         data['year'] = match.group(1)
+        year = data['year']
     else:
         data.pop('year', '')
 
@@ -101,7 +102,6 @@ def create_bibtex_entry(data):
         else:
             data.pop('pages', '')
 
-    year = data['year']
     author_words = data.get('author', '').split()
     first_author = author_words[0] if author_words else 'unknown'
     bibtex_id = f"{first_author}{year}" if year else first_author