3Rosen S. Hedonic prices and implicit markets: prod- uct differentiation in pure competition[J]. The Journal of Political Economy, 1974, 82(1) : 34-55.
4Fransoo J C, Bertrand J W M. An aggregate capacity estimation model for the evaluation of railroad passing constructions [ J 1. Transportation Research Part A: Policy and Practice, 2000, 34(1 ) : 35-49.