diff --git a/grep.1 b/grep.1
index 0091916..cb9ae47 100644
--- a/grep.1
+++ b/grep.1
@@ -16,7 +16,8 @@
 searches the input files for lines that match the
 .Ar pattern ,
 a regular expression as defined in
-.Xr regex 7 .
+.Xr regex 7 or
+.Xr re_format 7 .
 By default each matching line is printed to stdout.
 If no
 .Ar file
@@ -83,7 +84,8 @@ An error occurred.
 .El
 .Sh SEE ALSO
 .Xr sed 1 ,
-.Xr regex 7
+.Xr regex 7 ,
+.Xr re_format 7
 .Sh STANDARDS
 The
 .Nm
diff --git a/nl.1 b/nl.1
index 5b30524..93c428c 100644
--- a/nl.1
+++ b/nl.1
@@ -63,7 +63,8 @@ This is the default.
 Only lines matching
 .Ar expr
 according to
-.Xr regex 7 .
+.Xr regex 7 or
+.Xr re_format 7 .
 .El
 .It Fl d Ar delim
 Set