diff --git a/src/pkg/mime/grammar.go b/src/pkg/mime/grammar.go
index e60cbb8df74..6e319ff8be8 100644
--- a/src/pkg/mime/grammar.go
+++ b/src/pkg/mime/grammar.go
@@ -9,13 +9,13 @@ import (
 )
 
 // isTSpecial returns true if rune is in 'tspecials' as defined by RFC
-// 1531 and RFC 2045.
+// 1521 and RFC 2045.
 func isTSpecial(rune int) bool {
 	return strings.IndexRune(`()<>@,;:\"/[]?=`, rune) != -1
 }
 
 // IsTokenChar returns true if rune is in 'token' as defined by RFC
-// 1531 and RFC 2045.
+// 1521 and RFC 2045.
 func IsTokenChar(rune int) bool {
 	// token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
 	//             or tspecials>
diff --git a/src/pkg/mime/mediatype.go b/src/pkg/mime/mediatype.go
index f28ff3e9681..a270cb9370b 100644
--- a/src/pkg/mime/mediatype.go
+++ b/src/pkg/mime/mediatype.go
@@ -31,7 +31,7 @@ func validMediaTypeOrDisposition(s string) bool {
 }
 
 // ParseMediaType parses a media type value and any optional
-// parameters, per RFC 1531.  Media types are the values in
+// parameters, per RFC 1521.  Media types are the values in
 // Content-Type and Content-Disposition headers (RFC 2183).  On
 // success, ParseMediaType returns the media type converted to
 // lowercase and trimmed of white space and a non-nil params.  On