diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -39,3 +39,7 @@
 ## 0.4.2.0 -- 2020-11-19
 
 * Fourth version revised B. Added two new functions partitionG to the module.
+
+## 0.5.0.0 -- 2021-06-28
+
+* Fifth version. Added a new module Data.SubG.Unfold inspired by: https://www.works-hub.com/learn/number-anamorphisms-aka-unfolds-explained-50e1a by Marty Stumpf.
diff --git a/Data/SubG/Unfold.hs b/Data/SubG/Unfold.hs
new file mode 100644
--- /dev/null
+++ b/Data/SubG/Unfold.hs
@@ -0,0 +1,37 @@
+-- |
+-- Module      :  Data.SubG.Unfold
+-- Copyright   :  (c) OleksandrZhabenko 2021
+-- License     :  MIT
+-- Stability   :  Experimental
+-- Maintainer  :  olexandr543@yahoo.com
+--
+-- Generalization of the 'Data.List.unfoldr' for the data type that has 'InsertLeft' and 'Monoid' instances.
+-- Inspired by: https://www.works-hub.com/learn/number-anamorphisms-aka-unfolds-explained-50e1a by Marty Stumpf.
+
+module Data.SubG.Unfold (
+  unfoldG
+  , iterateG
+) where
+
+import Data.SubG
+import Data.Maybe (isJust, fromJust)
+import Data.Monoid
+
+-- | Inspired by: https://hackage.haskell.org/package/base-4.14.0.0/docs/src/Data.OldList.html#words
+-- and: Graham Hutton. A tutorial on the universality and expressiveness of fold. /J. Functional Programming/ 9 (4): 355–372, July 1999.
+-- that is available at the URL: https://www.cs.nott.ac.uk/~pszgmh/fold.pdf.
+-- Also inspired by: https://www.works-hub.com/learn/number-anamorphisms-aka-unfolds-explained-50e1a by Marty Stumpf.
+-- Generalizes the 'Data.List.unfoldr' function not only for lists, but for the data type that has 'InsertLeft' and 'Monoid' instances.
+unfoldG :: (InsertLeft t a, Monoid (t a)) => (a -> Maybe (a, a)) -> a -> t a
+unfoldG p x
+ | isJust (p x) = x %@ unfoldG p (snd . fromJust . p $ x)
+ | otherwise = mempty
+
+-- | Inspired by: https://hackage.haskell.org/package/base-4.14.0.0/docs/src/Data.OldList.html#words
+-- and: Graham Hutton. A tutorial on the universality and expressiveness of fold. /J. Functional Programming/ 9 (4): 355–372, July 1999.
+-- that is available at the URL: https://www.cs.nott.ac.uk/~pszgmh/fold.pdf.
+-- Also inspired by: https://www.works-hub.com/learn/number-anamorphisms-aka-unfolds-explained-50e1a by Marty Stumpf.
+-- Generalizes the 'Prelude.iterate' function not only for lists, but for the data type that has 'InsertLeft' and 'Monoid' instances.
+iterateG :: (InsertLeft t a, Monoid (t a)) => (a -> a) -> a -> t a
+iterateG f = unfoldG (\x -> Just (x, f x))
+{-# INLINE iterateG #-}
diff --git a/subG.cabal b/subG.cabal
--- a/subG.cabal
+++ b/subG.cabal
@@ -2,7 +2,7 @@
 -- see http://haskell.org/cabal/users-guide/
 
 name:                subG
-version:             0.4.2.0
+version:             0.5.0.0
 synopsis:            Some extension to the Foldable and Monoid classes.
 description:         Introduces a new class InsertLeft -- the class of types of values that can be inserted from the left to the Foldable structure that is a data that is also the Monoid instance. Also contains some functions to find out both minimum and maximum elements of the finite Foldable structures.
 homepage:            https://hackage.haskell.org/package/subG
@@ -17,7 +17,7 @@
 cabal-version:       >=1.10
 
 library
-  exposed-modules:     Data.SubG, Data.MinMax, Data.MinMax3Plus, Data.MinMax.Preconditions, Data.MinMax3Plus.Preconditions
+  exposed-modules:     Data.SubG, Data.SubG.Unfold, Data.MinMax, Data.MinMax3Plus, Data.MinMax.Preconditions, Data.MinMax3Plus.Preconditions
   -- other-modules:
   other-extensions:    MultiParamTypeClasses, FlexibleInstances
   build-depends:       base >=4.8 && <4.15