Table 2. Dissimilarity matrix of studies' characteristics based on the below of Table 1
		Witt et al., 2004	Wang et al., 2007	Hong et al., 2008	Hiby et al., 2008	Vargas et al., 2009	Faridi et al., 2009	Khosravifar et al., 2011	Ozturk et al., 2012	Djulejic et al., 2015	Dambaeva et al. 2016	Our study
1	Witt et al., 2004	0	0.33	0.33	0.33	0.16	0.33	0.33	0.50	0.50	0.83	0.16
2	Wang et al., 2007	0.33	0	0	0.50	0.50	0.33	0.50	0.66	0.66	1	0.33
3	Hong et al., 2008	0.33	0	0	0.50	0.50	0.33	0.50	0.66	0.66	0.83	0.33
4	Hiby et al., 2008	0.33	0.50	0.50	0	0.50	0.50	0.33	0.66	0.50	0.83	0.33
5	Vargas et al., 2009	0.16	0.50	0.50	0.50	0	0.50	0.50	0.33	0.66	0.66	0.33
6	Faridi et al., 2009	0.33	0.33	0.33	0.50	0.50	0	0.50	0.66	0.66	1	0.33
7	Khosravifar et al., 2011	0.33	0.50	0.50	0.33	0.50	0.50	0	0.66	0.50	0.83	0.33
8	Ozturk et al., 2012	0.50	0.66	0.66	0.66	0.33	0.66	0.66	0	0.66	0.66	0.50
9	Djulejic et al., 2015	0.50	0.66	0.66	0.50	0.66	0.66	0.50	0.66	0	0.66	0.50
10	Dambaeva et al., 2016	0.83	1	0.83	0.83	0.66	1	0.83	0.66	0.66	0	0.83
11	Our original study	0.16	0.33	0.33	0.33	0.33	0.33	0.33	0.50	0.50	0.83	0