diff --git a/monetdb-mapi.cabal b/monetdb-mapi.cabal
--- a/monetdb-mapi.cabal
+++ b/monetdb-mapi.cabal
@@ -1,7 +1,7 @@
 name:                monetdb-mapi
-version:             0.1.0.0
+version:             0.1.0.1
 synopsis:            Mid-level bindings for the MonetDB API (mapi)
--- description:         
+description:         This library provides a convenient API to work with MonetDB.
 license:             BSD3
 license-file:        LICENSE
 author:              Moritz Bruder
@@ -20,7 +20,7 @@
   exposed-modules:     Database.MonetDB.Mapi
   -- other-modules:       
   -- other-extensions:    
-  build-depends:       base >=4.8 && <4.10,
+  build-depends:       base >=4.8 && <4.12,
                        bindings-monetdb-mapi ==0.1.*
 
   hs-source-dirs:      src
diff --git a/src/Database/MonetDB/Mapi.hs b/src/Database/MonetDB/Mapi.hs
--- a/src/Database/MonetDB/Mapi.hs
+++ b/src/Database/MonetDB/Mapi.hs
@@ -6,13 +6,14 @@
     , ErrorType(..)
 
     -- * Connection parameters
+    , Database
     , Lang(..)
     , ConInfo(..)
     , emptyConInfo
     , defConInfo
 
     -- * Connection handling
-    , Connection(..)
+    , Connection
     , connect
     , disconnect
     , withConnection
@@ -32,26 +33,29 @@
 import qualified Bindings.MonetDB.Mapi as B
 import qualified Control.Exception     as E
 
+-- | Error types that may occur within MonetDB.
+data ErrorType
+    = Default String
+    | Timeout
+    | Server String
+    deriving Show
+
 -- | Some IO actions might throw 'MapiError'.
-data MapiError = MapiError
-               { errorType    :: ErrorType
-               }
-               deriving Show
+newtype MapiError
+    = MapiError
+    { errorType :: ErrorType
+    } deriving Show
 
 instance E.Exception MapiError where
     toException                       = E.SomeException
     fromException (E.SomeException e) = cast e
 
-data ErrorType = Default String
-               | Timeout
-               | Server String
-               deriving Show
-
 -- | The language to be used for a connection.
-data Lang = Sql
-          | Mil
-          | Mal
-          | XQuery
+data Lang
+    = Sql
+    | Mil
+    | Mal
+    | XQuery
 
 fromLang :: Lang -> String
 fromLang l = case l of
@@ -72,7 +76,6 @@
     if e == B.cMERROR
     then do
         cstr <- B.mapi_error_str mapi
-        print cstr
         s <- peekCString cstr
         E.throwIO $ MapiError $ Default s
     else when (e == B.cMTIMEOUT) $ E.throwIO $ MapiError Timeout
@@ -134,10 +137,14 @@
 -- [["42", "23"]]
 --
 withConnection :: ConInfo -> Lang -> (Connection -> IO a) -> IO a
-withConnection ci l f = E.bracket (connect ci l) disconnect f
+withConnection ci l = E.bracket (connect ci l) disconnect
 
 
--- TODO rework Result and Query, that mechanism is terrible
+-- TODO rework Result and Query, that mechanism is terrible:
+-- The issue here is that some components may be used multiple times, but that
+-- is a type of error. A representation is required that does not allow using
+-- resources several times in IO actions (e.g. inversion of control with a
+-- function).
 
 type QueryForeignPtr = ForeignPtr ()
 
@@ -195,5 +202,6 @@
     r <- execute q
     fetchRows r
 
+-- | Run a query and ignore the result.
 quickQuery_ :: Connection -> String -> IO ()
 quickQuery_ c s = query c s >>= void . execute