diff --git a/Database/HSparql/Connection.hs b/Database/HSparql/Connection.hs
--- a/Database/HSparql/Connection.hs
+++ b/Database/HSparql/Connection.hs
@@ -104,8 +104,9 @@
     let uri = ep ++ "?" ++ urlEncodeVars [("query", createAskQuery q)]
         hdr1 = Header HdrUserAgent "hsparql-client"
         hdr2 = Header HdrAccept "text/plain"
-        hdr3 = Header HdrAcceptCharset "utf-8"
-        request  = insertHeaders [hdr1,hdr2,hdr3] (getRequest uri)
+        hdr3 = Header HdrAccept "text/boolean"
+        hdr4 = Header HdrAcceptCharset "utf-8"
+        request  = insertHeaders [hdr1,hdr2,hdr3,hdr4] (getRequest uri)
     response <- simpleHTTP request >>= getResponseBody
     return $ parseAsk response
 
@@ -131,7 +132,7 @@
 
 -- |Connect to remote 'EndPoint' and construct 'TriplesGraph' from given
 --  'ConstructQuery' action. /Provisional implementation/.
-constructQuery :: forall rdf. (RDF rdf) => Database.HSparql.Connection.EndPoint -> Query ConstructQuery -> IO rdf
+constructQuery :: (Rdf a) => Database.HSparql.Connection.EndPoint -> Query ConstructQuery -> IO (RDF a)
 constructQuery ep q = do
     let uri      = ep ++ "?" ++ urlEncodeVars [("query", createConstructQuery q)]
     rdfGraph <- httpCallForRdf uri
@@ -142,7 +143,7 @@
 
 -- |Connect to remote 'EndPoint' and construct 'TriplesGraph' from given
 --  'ConstructQuery' action. /Provisional implementation/.
-describeQuery :: forall rdf. (RDF rdf) => Database.HSparql.Connection.EndPoint -> Query DescribeQuery -> IO rdf
+describeQuery :: (Rdf a) => Database.HSparql.Connection.EndPoint -> Query DescribeQuery -> IO (RDF a)
 describeQuery ep q = do
     let uri      = ep ++ "?" ++ urlEncodeVars [("query", createDescribeQuery q)]
     rdfGraph <- httpCallForRdf uri
@@ -152,7 +153,7 @@
     
 -- |Takes a generated uri and makes simple HTTP request,
 -- asking for RDF N3 serialization. Returns either 'ParseFailure' or 'RDF'
-httpCallForRdf :: RDF rdf => String -> IO (Either ParseFailure rdf)
+httpCallForRdf :: Rdf a => String -> IO (Either ParseFailure (RDF a))
 httpCallForRdf uri = do
   let h1 = mkHeader HdrUserAgent "hsparql-client"
       h2 = mkHeader HdrAccept "text/turtle"
diff --git a/hsparql.cabal b/hsparql.cabal
--- a/hsparql.cabal
+++ b/hsparql.cabal
@@ -1,6 +1,6 @@
 Name:          hsparql
 Homepage:      https://github.com/robstewart57/hsparql
-Version:       0.2.8
+Version:       0.2.9
 Synopsis:      A SPARQL query generator and DSL, and a client to query a SPARQL server.
 Category:      Database
 Description: