diff --git a/data/aux/bibliography4ht.tex b/data/aux/bibliography4ht.tex
index 5ba07b3..91f7607 100644
--- a/data/aux/bibliography4ht.tex
+++ b/data/aux/bibliography4ht.tex
@@ -42,7 +42,7 @@
   \printfield{volume}%
   \iffieldundef{number}
      {}
-      {\mkbibparens{\printfield{number}}}%
+     {\printfield[parens]{number}}
   \setunit{\addcomma\space}%
   \printfield{eid}%
   \setunit{\addspace}%