“…Several methods of analysis and synthesis can be used in theoretical reviews (Paré et al, 2015). In this review, a constant comparison method was selected as the systematic analytic method (Skate & Perry, 2008). A constant comparison method helps to convert extracted data from articles into categories, to facilitate the identification of patterns, themes, variations and relationships (Dye, Schaltz, Rosenberg, & Coleman, 2000;Glaser, 1978;Glaser & Strauss, 1967;Miles & Huberman, 1994;Patton, 2002;Strauss & Corbin, 1998;Vivar, Arantzamendi, López-Dicastillo, & Gordo Luis, 2010;Whittemore & Knafl, 2005) .…”