diff --git a/NanoProlog.cabal b/NanoProlog.cabal
--- a/NanoProlog.cabal
+++ b/NanoProlog.cabal
@@ -1,5 +1,5 @@
 Name:                NanoProlog
-Version:             0.1.1
+Version:             0.1.2
 Synopsis:            Very small  interpreter for a Prolog-like language
 Description:         This package was developed to demonstrate the ideas behind
                      the Prolog language. It contains a very small interpreter
diff --git a/src/Language/Prolog/NanoProlog/Lib.hs b/src/Language/Prolog/NanoProlog/Lib.hs
--- a/src/Language/Prolog/NanoProlog/Lib.hs
+++ b/src/Language/Prolog/NanoProlog/Lib.hs
@@ -7,6 +7,8 @@
      LowerCase
   ,  Result(..)
   ,  Rule((:<-:))
+  ,  Subst(..)
+  ,  Taggable(..)
   ,  Term(..)
   ,  emptyEnv
   ,  enumerateDepthFirst
@@ -15,7 +17,6 @@
   ,  pTerm
   ,  show'
   ,  solve
-  ,  subst
   ,  startParse
   ,  unify
   ) where