Muuls, Mirabelle; Pisu, Mauro - London School of Economics (LSE) - 2007
. The same is true if we consider the number of products traded. With regard to productivity differentials, firms that both …-traders. These results point to the presence of fixed costs; not only of exporting, but also of importing and to a process of self …-selection in both export and import markets. Also, the productivity advantage of exporters reported in the literature may be …