This is a preface of the translation of the 1967 paper by Linis and Maksim, “On the problem of constructing routes” (in Russian) (in the Proceedings of the Institute of Civil Aviation Engineering, Issue 102, pp. 36-45). It marks 50-year to the deficit function (DF) model initially developed in this 1967 work; the DF model then paved the way to further research of vehicle-fleet management in terms of optimal routing and scheduling. The merit of this translation is to describe the roots of the DF modelling to enable further studies to emerge with more contributions.
10. Salzborn F.J.M. (1974) Minimum fleet size models for transportation systems. In: D.J. Buckley (Ed.) Proceedings of the 6th International Symposium on Transportation & Traffic Theory (ISTTT6) Sydney Australia 607-624.