1. P. P. Borodavkin, V. L. Berezin, and S. Yu. Ruderman, Selection of Optimum Layouts for Main Pipelines [in Russian], Nedra, Moscow (1974).
2. R. Bellman and S. Dreyfus, Applied Dynamic Programming, Princeton Univ. Press (1962).
3. L. B. Abraitis, R. I. Sheinauskas, and V. A. Zhilevichyus, Computer Automation of Planning [in Russian], Sov. Radio, Moscow (1978).
4. G. A. Strekachinskii, A. A. Ordin, and V. A. Fedorin, Optimum Arrangement of Transport Networks on the Surfaces of Coal Mines [in Russian], Nauka, Novosibirsk (1981).
5. Application and Generalization of Steiner's Problem for Formulating and Solving Certain Problems in Space Saving [in Russian], TsÉMI, Moscow (1968).