diff --git a/gscholar-rss.cabal b/gscholar-rss.cabal
--- a/gscholar-rss.cabal
+++ b/gscholar-rss.cabal
@@ -1,5 +1,5 @@
 name:                gscholar-rss
-version:             0.2.1.0
+version:             0.2.2.0
 synopsis:            scrapes google scholar, provides RSS feed
 description:         A simple Google Scholar scraper, providing RSS/Atom
                      feeds. Check homepage for manual and examples.
@@ -19,10 +19,14 @@
 executable gscholar-rss
   main-is:             Main.hs
   build-depends:       base == 4.*,
-                       scalpel-core == 0.5.*,
-                       feed ^>= 1.0.1.0,
+                       scalpel-core >= 0.5 && < 0.7,
+                       feed >= 1.0.1.0 && < 1.3,
                        text == 1.2.*,
                        http-conduit == 2.3.*,
                        uri == 0.1.*
   hs-source-dirs:      src
   default-language:    Haskell2010
+
+source-repository head
+    type:     darcs
+    location: http://www.ariis.it/link/repos/gscholar-rss/
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -118,9 +118,9 @@
                       id
                       (U.parseURI $ T.unpack url)
 
-          condA = let rn = maybe (error "regname") id
-                                 (U.uriRegName uri)
-                  in L.isPrefixOf "books.google" rn
+          condA = case U.uriRegName uri of
+                    Nothing -> False -- citation, no uri
+                    Just rn -> L.isPrefixOf "books.google" rn
 
           filtFun :: (String, String) -> Bool
           filtFun (l, _) = not (elem l ["ots", "sig"])