“…Two types of issues are discernible in this literature. One is the quota (VERs) with homogenous or horizontally differentiated goods in the case of duopoly (Harris, 1985;Rotemberg and Saloner, 1989;Gaudet and Salant, 1991;Melitz, 2005;Moore, 2005;and Giacomo and Lambertini, 2007) and the other one emphasizes the effect of quota (VERs), under the vertical differentiation model (Rodriguez, 1979;Das and Donnenfeld, 1987;Krishna, 1987;Ries, 1993;Herguera et al, 2000;Zhou et al, 2002;and Boccard and Wauthy, 2006). Please see Walker (2015) for a complete survey of this literature on the import quota policy and VERs.…”