diff --git a/lean.bib b/lean.bib
index a7433e069..5de076bdc 100644
--- a/lean.bib
+++ b/lean.bib
@@ -10,7 +10,8 @@ @Article{         ABKNT_2024
                   and Nuccio Mortarino Majno di Capriglio, Filippo and Topaz,
                   Adam},
   year          = {2024},
-  pages         = {1-28}
+  pages         = {1-28},
+  tags          = {formalization, lean4}
 }
 
 @InProceedings{   AGLST23,