diff --git a/man/gnt-backup.sgml b/man/gnt-backup.sgml
index 8ec4e69..115f6b3 100644
--- a/man/gnt-backup.sgml
+++ b/man/gnt-backup.sgml
@@ -206,9 +206,8 @@
<varlistentry>
<term>mac</term>
<listitem>
- <simpara>either a value or <constant>GENERATE</constant>
- to generate a new unique MAC, or
- <constant>AUTO</constant> to reuse the old MAC</simpara>
+ <simpara>either a value or 'generate' to generate a new
+ unique MAC, or 'auto' to reuse the old MAC</simpara>
</listitem>
</varlistentry>
<varlistentry>
diff --git a/man/gnt-instance.sgml b/man/gnt-instance.sgml
index 07bb61c..17ab1b9 100644
--- a/man/gnt-instance.sgml
+++ b/man/gnt-instance.sgml
@@ -200,8 +200,8 @@
<varlistentry>
<term>mac</term>
<listitem>
- <simpara>either a value or <constant>GENERATE</constant>
- to generate a new unique MAC</simpara>
+ <simpara>either a value or 'generate' to generate a
+ new unique MAC</simpara>
</listitem>
</varlistentry>
<varlistentry>
--
1.7.1
LGTM