diff --git a/deferred-folds.cabal b/deferred-folds.cabal
--- a/deferred-folds.cabal
+++ b/deferred-folds.cabal
@@ -1,5 +1,5 @@
 name: deferred-folds
-version: 0.9.11
+version: 0.9.12
 category: Folding
 synopsis: Abstractions over deferred folds
 description:
@@ -9,7 +9,7 @@
 homepage: https://github.com/metrix-ai/deferred-folds
 bug-reports: https://github.com/metrix-ai/deferred-folds/issues
 author: Nikita Volkov <nikita.y.volkov@mail.ru>
-maintainer: Metrix.AI Tech Team <tech@metrix.ai>
+maintainer: Nikita Volkov <nikita.y.volkov@mail.ru>
 copyright: (c) 2018, Metrix.AI
 license: MIT
 license-file: LICENSE
diff --git a/library/DeferredFolds/Defs/Unfoldr.hs b/library/DeferredFolds/Defs/Unfoldr.hs
--- a/library/DeferredFolds/Defs/Unfoldr.hs
+++ b/library/DeferredFolds/Defs/Unfoldr.hs
@@ -122,6 +122,12 @@
 intMapAssocs intMap =
   Unfoldr (\ step init -> IntMap.foldrWithKey (\ key value state -> step (key, value) state) init intMap)
 
+{-| Keys of a hash-map -}
+{-# INLINE hashMapKeys #-}
+hashMapKeys :: HashMap key value -> Unfoldr key
+hashMapKeys hashMap =
+  Unfoldr (\ step init -> HashMap.foldrWithKey (\ key _ state -> step key state) init hashMap)
+
 {-| Associations of a hash-map -}
 {-# INLINE hashMapAssocs #-}
 hashMapAssocs :: HashMap key value -> Unfoldr (key, value)