1. V.V. Zorin and P.J. Ekel, Methods of discrete optimization of electric supply systems (in Russian), Izvestija Acad. of Sciences USSR. Energetika i Transport, (1980) 5, 25–37, translated into English as Allerton Press, Inc.
2. M.R. Garey and D.S. Johnson, Computers and Intractability: A Guide to the Theory of NP-completeness, W.H. Freemaan and Co., San Francisco (1979).
3. E.A. Bersin, Optimal Resources Distribution and Elements of System Synthesis (in Russian), Soviet Radio, Moscow (1974).
4. G. Dobson, Worst-case analysis of greedy heuristics for integer programming with nonnegative data, Mathematics of Operations Research, 7 (1983) 4, 515–531.
5. V.V. Zorin, V.A. Popov, P.J. Ekel, V.V. Tislenko, K. Zabi-Zabi and V.V. Tkachenko, Models of safety optimization in distributed systems (in Russian), Energetika i Electrifikacija, (1988) 3, 46–49.