diff --git a/library/General_Types.ttcn b/library/General_Types.ttcn
index 612d5c7e1..924f28bab 100644
--- a/library/General_Types.ttcn
+++ b/library/General_Types.ttcn
@@ -70,10 +70,14 @@ group SimpleNativeTypes {
   type bitstring BIT10 length(10) with { variant "FIELDLENGTH(10)" };
   type bitstring BIT11 length(11) with { variant "FIELDLENGTH(11)" };
   type bitstring BIT12 length(12) with { variant "FIELDLENGTH(12)" };
+  type bitstring BIT13 length(13) with { variant "FIELDLENGTH(13)" };
   type bitstring BIT14 length(14) with { variant "FIELDLENGTH(14)" };
   type bitstring BIT15 length(15) with { variant "FIELDLENGTH(15)" };
   type bitstring BIT16 length(16) with { variant "FIELDLENGTH(16)" };
   type bitstring BIT24 length(24) with { variant "FIELDLENGTH(24)" };
+  type bitstring BIT28 length(28) with { variant "FIELDLENGTH(28)" };
+  type bitstring BIT29 length(29) with { variant "FIELDLENGTH(29)" };
+  type bitstring BIT30 length(30) with { variant "FIELDLENGTH(30)" };
   type bitstring BIT31 length(31) with { variant "FIELDLENGTH(31)" };
   type bitstring BIT32 length(32) with { variant "FIELDLENGTH(32)" };
   type bitstring BIT56 length(56) with { variant "FIELDLENGTH(56)" };