diff --git a/example/euclidean.hs b/example/euclidean.hs
--- a/example/euclidean.hs
+++ b/example/euclidean.hs
@@ -42,8 +42,6 @@
     else do
         i <- lift get -- which step is this?
         lift (put (i+1))
-        desc1 <- descX x y
-        desc2 <- descY x y
         xi <- (func updateX =<< (descX x y)) <%> x <%> y
         yi <- (func updateY =<< (descY x y)) <%> x <%> y
         xi `named` ("x"++(show i))
diff --git a/provenience.cabal b/provenience.cabal
--- a/provenience.cabal
+++ b/provenience.cabal
@@ -1,5 +1,5 @@
 name:                provenience
-version:             0.1.0.1
+version:             0.1.0.2
 synopsis:            Computations that automatically track data dependencies
 description:         see README.md
 license:             GPL-3
@@ -22,7 +22,7 @@
 -- tested against stackage lts-6.35 up to lts-14.22
   build-depends:       base >= 4.7 && < 5
                      , mtl >= 2.2.1 && <= 2.2.2
-                     , fgl >= 5.5.3.1 && <= 5.7.0.1
+                     , fgl >= 5.5.3.1 && <= 5.7.0.2
                      , pandoc >= 1.16 && <= 2.7.3
                      , blaze-markup >= 0.7.1.1 && <= 0.8.2.3
                      , aeson >= 0.11.3.0 && <= 1.4.6.0
diff --git a/src/Control/Provenience.hs b/src/Control/Provenience.hs
--- a/src/Control/Provenience.hs
+++ b/src/Control/Provenience.hs
@@ -131,7 +131,7 @@
     }
 -- | Variables are internally numbered by 'Node' = 'Int' 
 -- and have an alternative value 'Representation' @alt@. 
--- Futher each variable has a Pandoc 'description' (set by '<?') 
+-- Further each variable has a Pandoc 'description' (set by '<?') 
 -- and optionally a 'shortname' set by 'named' which is a 'String' 
 -- to be used in hyperlinks. 
 data VariableStore alt = VariableStore {
@@ -156,7 +156,8 @@
 -- | Every 'Variable' has an 'identifier' in the data flow graph. 
 data Variable a = Variable {
     identifier :: Node,
-    value :: a}
+    value :: a -- ^ dereference
+    }
 instance Functor Variable where
     fmap f x = x {value = f (value x)}
 instance Show a => Show (Variable a) where
@@ -168,6 +169,12 @@
 
 -- | A 'Monad' transformer that keeps track of data dependencies
 type ProvenienceT alt m a = StateT (VariableStore alt) m (Variable a)
+-- TODO: This does not parallelize well. Use Parallel-Arrow-Multicore
+-- to define an arrow isomorphic to 
+-- (a -> b, a -> VariableStore alt -> VariableStore alt)
+-- so that the pure computation can be parallelized.
+
+
 -- | @'Provenience' = 'ProvenienceT' () 'Identity'@
 type Provenience a = State (VariableStore ()) (Variable a)
 -- | Action on the 'VariableStore'