"Mundell and Markusen each wrote classic papers on the relationship between trade and factor movement. Mundell showed that substitution holds in the Heckscher-Ohlin model. Markusen challenged the substitution result and showed in five different models that removing barriers to factor movement...

How firms react to a given shock may depend on the degree to which rivals are present and on whether potentially viable entrants to that market exist. A preferred supplier market presence and threat of entry lessen a nonmember country's price reaction to most-favored-nation trade liberalization...