Table 2.

Stars-rating based on the Modified Newcastle–Ottawa Scale

Aritcle	Item 1	Item 2	Item 3	Item 4	Item 5	Item 6	Total
Wojcicki, 2015	*	*	*	-	-	*	4
van Heerde, 2012	*	*	*	*	*	*	6
Räty, 2015	*	-	*	-	-	*	3
Chuong T. Tran, 2012	*	*	*	-	-	*	4
Jiang, 2017	*	*	*	-	-	*	4
Abraham, 2003	*	*	-	-	-	*	3
Vitali, 2014	*	*	*	-	-	*	4
de Castro, 2009	*	*	-	-	-	*	3
Yarandi,2014	*	-	*	*	-	*	4
Javed, 2021	*	-	-	-	-	*	2