6Ferland J A, Michelon P. The vehicle scheduling problem with multiple vehicle types[J]. Journal of the Operation Research Society, 1988,39 : 577 - 583.
7Blanton J L, et al. Multiple vehicle routing with time and capacity constraints using genetic algorithms [A]. Proceedings of the Fifth International Conference on Genetic Algorithms[C]. LosAltas, CA, 1993: 452-459.
