This paper considers an incumbent firm that is faced with a potential entrant in a vertically differentiated market. It demonstrates than an incumbent firm cannot prevent entry through product proliferation because of a commitment problem.

We introduce technological differences in a Heckscher-Ohlin model and study how the technology and endowment differences interact to determine the effects of trade on factor prices.

Models which estimate influenza mortality probably overestimate this mortality because their baseline estimates include only nonepidemic weeks. We present a stochastic frontier estimation model which better reflects influenza mortality.