diff --git a/paper.bib b/paper.bib
index 12f93c8..2dc5da4 100644
--- a/paper.bib
+++ b/paper.bib
@@ -8,7 +8,7 @@ @article{aiida
 }
 @software{AIMAll,
 url = {aim.tkgristmill.com},
-version=19.10.12
+version={19.10.12}
 year = 2019,
 Author = {Todd A. Keith},
 publisher = TK Gristmill Software,