“…Accordingly, the discussion of related variety, while conceptually alluring, is hard to pinpoint empirically, and has yet to be verified empirically in the context of CBRIS. Consequently, the empirical literature on CBRIS has concentrated on studying a single, or few types of, proximity including cognitive distance (Makkonen, 2015), geographical proximity or physical barriers (Bijaoui et al, 2011;Hansen, 2013;Kiryushin et al, 2013) and institutional gaps (van den Broek & Smulders, 2014;. What is noticeable, is that in the early literature on CBRIS, the empirical validations of proximity in CBR were actually more diverse and ambitious than they have been recently (Appendix 1).…”