diff --git a/examples/LangExt.hs b/examples/LangExt.hs
--- a/examples/LangExt.hs
+++ b/examples/LangExt.hs
@@ -24,6 +24,8 @@
 
 import Data.HList.Label4
 import Data.HList.TypeEqGeneric1
+
+
 import Data.HList.TypeCastGeneric1
 
 import Language.AbstractSyntax.TTTAS (match, Equal(..))
@@ -190,7 +192,7 @@
          addProds   -<  (factor,  ( iI semPar    "(" exp ")" Ii )    )
          
          exportNTs  -< imported
-
+{-
 mapNTProds :: Symbol b TNonT env -> Symbol b TNonT env -> PreProductions TL env a -> PreProductions TL env a
 mapNTProds s1 s2 (PP prds) = PP $ map (mapNTProd s1 s2) prds
 
@@ -199,9 +201,9 @@
 mapNTProd r1 r2 (Star f  g)     = Star (mapNTProd r1 r2 f) (mapNTProd r1 r2 g)
 mapNTProd (Nont r1) (Nont r2) (Sym (Nont r)) = case match r1 r of 
 						 (Just Eq) -> Sym (Nont r2)
-						 _Nothing  -> Sym (Nont r)
+						 Nothing   -> Sym (Nont r)
 mapNTProd _  _ p = p
-
+-}
 --gramOpts' gramOpts = gramOpts `extKeywordsTxt` [ "square", "pyth" ] `extSpecChars` "()[|]"
 
 
diff --git a/murder.cabal b/murder.cabal
--- a/murder.cabal
+++ b/murder.cabal
@@ -1,5 +1,5 @@
 name:               murder 
-version:            1.3.3
+version:            1.3.4
 cabal-version:      >= 1.2.3  
 license:            LGPL
 license-file:       COPYRIGHT
@@ -14,7 +14,7 @@
 extra-source-files: README, LICENSE-LGPL 
 library
         build-depends:      base>=4 && <5, template-haskell>=2.4.0.1, TTTAS>=0.4.1, AspectAG>=0.3.6.1,
-                            uulib>=0.9.12, uu-parsinglib >= 2.7.3.4, ListLike >= 3.1.0, containers>=0.3, HList>=0.2
+                            uulib>=0.9.12, uu-parsinglib >= 2.7.3.4, ListLike >= 3.1.0, containers>=0.3, HList>=0.2 && <0.3
         exposed-modules:    Language.Grammars.Grammar,
                             Language.Grammars.Grammar.AspectAG,  
                             Language.Grammars.Grammar.AG,  
diff --git a/src/Language/Grammars/Murder.hs b/src/Language/Grammars/Murder.hs
--- a/src/Language/Grammars/Murder.hs
+++ b/src/Language/Grammars/Murder.hs
@@ -53,6 +53,18 @@
       updateFinalEnv  -< 
          updateEnv (\_ -> PS $ (unPP prds)) (getRefNT nont)
 
+-- map references into the given productions
+mapNTProds :: Symbol b TNonT env -> Symbol b TNonT env -> PreProductions TL env a -> PreProductions TL env a
+mapNTProds s1 s2 (PP prds) = PP $ map (mapNTProd s1 s2) prds
+
+
+mapNTProd :: Symbol b TNonT env -> Symbol b TNonT env -> Prod TL a env -> Prod TL a env
+mapNTProd r1 r2 (Star f  g)     = Star (mapNTProd r1 r2 f) (mapNTProd r1 r2 g)
+mapNTProd (Nont r1) (Nont r2) (Sym (Nont r)) = case match r1 r of 
+						 (Just Eq) -> Sym (Nont r2)
+						 Nothing   -> Sym (Nont r)
+mapNTProd _  _ p = p
+
  
 -- close the grammar
 closeGram :: (forall env. ExtGram  env a nts)