diff --git a/lagrangian.cabal b/lagrangian.cabal
--- a/lagrangian.cabal
+++ b/lagrangian.cabal
@@ -10,7 +10,7 @@
 -- PVP summary:      +-+------- breaking API changes
 --                   | | +----- non-breaking API additions
 --                   | | | +--- code changes with no API change
-version:             0.2.0.0
+version:             0.2.0.1
 
 -- A short (one-line) description of the package.
 synopsis:            Solve lagrangian multiplier problems
diff --git a/src/Numeric/AD/Lagrangian.hs b/src/Numeric/AD/Lagrangian.hs
--- a/src/Numeric/AD/Lagrangian.hs
+++ b/src/Numeric/AD/Lagrangian.hs
@@ -23,5 +23,6 @@
 --  The first elements of the result pair are the arguments for the objective function at the minimum. 
 --  The second elements are the lagrange multipliers.
 module Numeric.AD.Lagrangian (
-    solve) where
-import Numeric.AD.Lagrangian.Internal (solve, feasible)
+    solve,
+    Constraint) where
+import Numeric.AD.Lagrangian.Internal (solve, feasible, Constraint)