1. M. Aigner and G. M. Ziegler, Proofs from THE BOOK, 2018, Berlin.
2. A. D. Aleksandrov, Convex Polyhedra, GITTL, Moscow-Leningrad (1950).
3. K. Ball, “An Elementary Introduction to Monotone Transportation,” Lect. Notes Math., 1850, 41–52 (2004).
4. E. G. Belousov, Introfuction to Convex Analysis and Integer Programming, Moscow State Univ., Moscow (1977).
5. W. Blaschke, Circle and Ball, Chelsea, New York (1949).