diff --git a/share/doc/papers/bufbio/bio.ms b/share/doc/papers/bufbio/bio.ms
index 936389bb756..123f8e7699b 100644
--- a/share/doc/papers/bufbio/bio.ms
+++ b/share/doc/papers/bufbio/bio.ms
@@ -7,6 +7,7 @@
 .\"
 .\" $FreeBSD$
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+.if n .ftr C R
 .nr PI 2n
 .TL
 The case for struct bio