+.SH BUGS
+The RFC822 group syntax
+(``group:user1,user2,user3;'')
+is not supported except in the special case of
+``group:;''
+because of a conflict with old berknet-style addresses.
+.SH SEE ALSO
+mail(1), sendmail(8);
+Crocker, D. H.,
+.ul
+Standard for the Format of Arpa Internet Text Messages,
+RFC822.