“…Finally, we added one book , four book chapters (Nieuwenhuis & Wells, 2003;Radgen, 2014;Visintin, 2014;Gaiardelli et al, 2014b) as well as four journal articles (Firnkorn & Müller, 2012;Wells & Orsato, 2005;Meier et al, 2010;Sundin & Bras, 2005) which were traced back from previous literature reviews but our search process failed to extract them. At the end of this process, our sample contained 22 studies.…”