diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -8,3 +8,8 @@
 
 * Second version. Added the new type constuctor UG3 to the UniquenessGeneral1 data type. Added new functions related to uniquenessPeriodsVector3. 
 
+## 0.3.0.0 -- 2020-09-09
+
+* Third version. Fixed issue with helpUPV3 function. 
+
+
diff --git a/String/Languages/UniquenessPeriods/Vector.hs b/String/Languages/UniquenessPeriods/Vector.hs
--- a/String/Languages/UniquenessPeriods/Vector.hs
+++ b/String/Languages/UniquenessPeriods/Vector.hs
@@ -67,10 +67,11 @@
                   V.unsafeIndex v2 $ 0),v3)) vs . V.partition (\(_,xs) -> xs == (snd . V.unsafeIndex x $ 0)) $ x in 
                     V.filter (\(ys,!zs) -> not (null ys) && (zs `notElem` whspss)) . V.unfoldr f $ v1
 
--- | Is used inside the 'uniquenessPeriodsVector3'. 
+-- | Is used inside the 'uniquenessPeriodsVector3'. Both list arguments of non-negative numbers (if not empty) must be sorted in the ascending order.
 helpUPV3 :: [Int] -> [Int] -> [Int]
 helpUPV3 (z:zs) (x:y:xs) 
  | compare ((x - z) * (y - z)) 0 == LT = (y - x):helpUPV3 zs (y:xs)
- | otherwise = helpUPV3 zs (x:y:xs)
+ | compare y z == GT = helpUPV3 zs (x:y:xs)
+ | otherwise = helpUPV3 (z:zs) (y:xs)
 helpUPV3 _ _ = []
 
diff --git a/uniqueness-periods-vector.cabal b/uniqueness-periods-vector.cabal
--- a/uniqueness-periods-vector.cabal
+++ b/uniqueness-periods-vector.cabal
@@ -2,7 +2,7 @@
 -- further documentation, see http://haskell.org/cabal/users-guide/
 
 name:                uniqueness-periods-vector
-version:             0.2.0.0
+version:             0.3.0.0
 synopsis:            Generalization of the uniqueness-periods and uniqueness-periods-general packages functionality.
 description:         Generalization of the uniqueness-periods and uniqueness-periods-general packages functionality.
 homepage:            https://hackage.haskell.org/package/uniqueness-periods-vector