1. F. Barahona: A solvable case for quadratic 0–1 programming,Discrete Appl. Math.,13 (1986) 23–26.
2. A. Bielecki: Quelques remarques sur la note précédente,Ann. Univ. Mariae Curie-Sklodowska, Sect. A,8 (1954) 101–103.
3. A. Bielecki, andK. Radiszewski: Sur les parallelepipedes inscrits dans les corps convexes,Ann. Univ. Mariae Curie-Sklodowska, Sect. A,8 (1954) 97–100.
4. C. Christensen: Kvadrat inskrevet i konveks figur, Mat. Tidskrift B,1950 (1950) 22–26.
5. S. A. Cook:The complexity of theorem-proving procedures,Proc. Third Ann. ACM Symp. on Theory of Computing, Association for Computing Machinery, New York,1971, 151–158.