Description of steps required to setup NFSv4 server is in nfsv4(4);

add reference to exports(5), since that's the obvious starting point
for searching for this.

usr.sbin/mountd/exports.5

@@ -28,7 +28,7 @@
 .\"     @(#)exports.5	8.3 (Berkeley) 3/29/95
 .\" $FreeBSD$
 .\"
-.Dd June 30, 2008
+.Dd December 3, 2009
 .Dt EXPORTS 5
 .Os
 .Sh NAME
@@ -473,6 +473,7 @@ operations on the server, so long as valid Kerberos credentials are provided.
 The machine grumpy.cis.uoguelph.ca is permitted to perform NFSv4 state
 operations on the server using AUTH_SYS credentials, as well as Kerberos ones.
 .Sh SEE ALSO
+.Xr nfsv4 4 ,
 .Xr netgroup 5 ,
 .Xr mountd 8 ,
 .Xr nfsd 8 ,