Update app.py

app.py

@@ -160,7 +160,9 @@ The list of languages used on the training of ALBERTI are:
 * Italian
 * Portuguese
 * Russian
-* Spanish""")
+* Spanish
+
+See https://arxiv.org/abs/2307.01387.""")
 
 col1, col2, col3 = st.columns(3)