1. R. Ahlswede, I. Wegener, Suchprobleme, Russian Edition with Appendix by M. Maljutov, 1981; English Edition with Supplement of recent Literature, in Wiley-Interscience Series in Discrete Mathematics and Optimization, 1987, ed. by R.L. Graham, J.K. Leenstra, R.E. Tarjan (Teubner Verlag, Stuttgart, 1979)