diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,3 +16,8 @@
 ## 0.1.3.0 -- 2020-11-26
 
 * First version revised C. Fixed issue with multiple application of the conversions in the Phonetic.Languages.Lists.Ukrainian.PropertiesFuncRepG module.
+
+## 0.1.3.1 -- 2020-11-26
+
+* First version revised D. Some code optimizations.
+
diff --git a/Phonetic/Languages/Lists/Ukrainian/PropertiesFuncRepG.hs b/Phonetic/Languages/Lists/Ukrainian/PropertiesFuncRepG.hs
--- a/Phonetic/Languages/Lists/Ukrainian/PropertiesFuncRepG.hs
+++ b/Phonetic/Languages/Lists/Ukrainian/PropertiesFuncRepG.hs
@@ -211,12 +211,7 @@
   -> ([[[S.UZPP2]]] -> [[Float]])
   -> Coeffs2
   -> FuncRep2 String Float c
-procB2F h g coeffs = D (\xs -> let ys = convertToProperUkrainianS . map (\x -> if x == '-' then ' ' else x) $ xs in  ((int2Float . fromEnum . diverse2GL " 01-" $ ys)*(eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words . mapMaybe f $ ys))) h
-  where f x
-          | x `elem` " 1-" = Just ' '
-          | x == '0' = Nothing
-          | otherwise = Just x
-        {-# INLINE f #-}
+procB2F h g coeffs = D (\xs -> let ys = convertToProperUkrainianS . map (\x -> if x == '-' then ' ' else x) $ xs in  ((int2Float . fromEnum . diverse2GL " 01-" $ ys)*(eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words1 . mapMaybe f $ ys))) h
 {-# INLINE procB2F #-}
 
 -- | Can be used to find out the minimum element.
@@ -225,12 +220,7 @@
   -> ([[[S.UZPP2]]] -> [[Float]])
   -> Coeffs2
   -> FuncRep2 String Float c
-procB2Fneg h g coeffs = D (\xs -> let ys = convertToProperUkrainianS . map (\x -> if x == '-' then ' ' else x) $ xs in  ((int2Float . negate . fromEnum . diverse2GL " 01-" $ ys)*(eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words . mapMaybe f $ ys))) h
-  where f x
-          | x `elem` " 1-" = Just ' '
-          | x == '0' = Nothing
-          | otherwise = Just x
-        {-# INLINE f #-}
+procB2Fneg h g coeffs = D (\xs -> let ys = convertToProperUkrainianS . map (\x -> if x == '-' then ' ' else x) $ xs in  ((int2Float . negate . fromEnum . diverse2GL " 01-" $ ys)*(eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words1 . mapMaybe f $ ys))) h
 {-# INLINE procB2Fneg #-}
 
 procB2InvF
@@ -241,13 +231,8 @@
 procB2InvF h g coeffs = D (\xs ->
   let !ys = convertToProperUkrainianS . map (\x -> if x == '-' then ' ' else x) $ xs
       !z = diverse2GL " 01-" ys in if z == 0 then  (eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds .
-         S.str2UZPP2s) . words . mapMaybe f $ ys) ** 2.0
-        else  ((eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words . mapMaybe f $ ys) / (int2Float . fromEnum $ z))) h
-    where f x
-           | x `elem` " 1-" = Just ' '
-           | x == '0' = Nothing
-           | otherwise = Just x
-          {-# INLINE f #-}
+         S.str2UZPP2s) . words1 . mapMaybe f $ ys) ** 2.0
+        else  ((eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words1 . mapMaybe f $ ys) / (int2Float . fromEnum $ z))) h
 {-# INLINE procB2InvF #-}
 
 -- | Can be used to find out the minimum element.
@@ -259,12 +244,18 @@
 procB2InvFneg h g coeffs = D (\xs ->
   let !ys = convertToProperUkrainianS . map (\x -> if x == '-' then ' ' else x) $ xs
       !z = diverse2GL " 01-" ys in if z == 0 then  (negate (eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds .
-         S.str2UZPP2s) . words . mapMaybe f $ ys) ** 2.0)
-        else  ((eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words . mapMaybe f $ ys) /
+         S.str2UZPP2s) . words1 . mapMaybe f $ ys) ** 2.0)
+        else  ((eval23Coeffs coeffs . mconcat . g . map (S.divVwls . S.reSyllableCntnts . S.groupSnds . S.str2UZPP2s) . words1 . mapMaybe f $ ys) /
           (int2Float . negate . fromEnum $ z))) h
-   where f x
-          | x `elem` " 1-" = Just ' '
-          | x == '0' = Nothing
-          | otherwise = Just x
-         {-# INLINE f #-}
 {-# INLINE procB2InvFneg #-}
+
+f x
+  | x == '0' = Nothing
+  | x /= '1' && x /= '-' = Just x
+  | otherwise = Just ' '
+{-# INLINE f #-}
+
+words1 xs = if null ts then [] else w : words1 s'' -- Practically this is an optimized version for this case 'words' function from Prelude.
+  where ts = dropWhile (== ' ') xs
+        (w, s'') = span (/= ' ') ts
+{-# NOINLINE words1 #-}
diff --git a/phonetic-languages-simplified-properties-lists.cabal b/phonetic-languages-simplified-properties-lists.cabal
--- a/phonetic-languages-simplified-properties-lists.cabal
+++ b/phonetic-languages-simplified-properties-lists.cabal
@@ -2,7 +2,7 @@
 -- For further documentation, see http://haskell.org/cabal/users-guide/
 
 name:                phonetic-languages-simplified-properties-lists
-version:             0.1.3.0
+version:             0.1.3.1
 synopsis:            A generalization of the uniqueness-periods-vector-properties package.
 description:         Is a simplified version of the functionality of the former one. Uses lists as main processment data.
 homepage:            https://hackage.haskell.org/package/phonetic-languages-simplified-properties-lists
@@ -20,6 +20,6 @@
   exposed-modules:     Phonetic.Languages.Lists.Ukrainian.PropertiesFuncRepG, Phonetic.Languages.Lists.Ukrainian.PropertiesSyllablesG
   -- other-modules:
   other-extensions:    BangPatterns, CPP
-  build-depends:       base >=4.7 && <4.15, vector >=0.11 && <0.14, phonetic-languages-rhythmicity >=0.1.2 && <1, phonetic-languages-simplified-common >=0.3 && <1, ukrainian-phonetics-basic >=0.3.1 && <1
+  build-depends:       base >=4.7 && <4.15, vector >=0.11 && <0.14, phonetic-languages-rhythmicity >=0.1.2 && <1, phonetic-languages-simplified-common >=0.3 && <1, ukrainian-phonetics-basic >=0.3.1.2 && <1
   -- hs-source-dirs:
   default-language:    Haskell2010