diff --git a/libasn1fix/asn1fix_crange.c b/libasn1fix/asn1fix_crange.c
index 1dbd0d3..907ffd6 100644
--- a/libasn1fix/asn1fix_crange.c
+++ b/libasn1fix/asn1fix_crange.c
@@ -1014,8 +1014,10 @@
 		return range;
 	case ACT_CA_EXC:	/* FROM("ABCD") EXCEPT FROM("AB") */
 		/*
-		 * X.691, #9.3.19:
+		 * X.691 (PER), #9.3.19:
 		 * EXCEPT and the following value set is completely ignored.
+		 * X.696 (OER), #8.2.6:
+		 * EXCEPT keyword and the following value set is completely ignored.
 		 */
 		assert(ct->el_count >= 1);
 		_range_free(range);