1. Adams, W., Johnson, T.: Improved linear programming-based lower bounds for the quadratic assignment problem. DIMACS 512 Ser. Discret. Math. Theor. Comput. Sci. 16, 43–77 (1994).
https://doi.org/10.1090/dimacs/016/02
2. AFNOR: Interfaces utilisateurs - Dispositions de clavier bureautique français, NF Z71–300 Avril 2019
3. Arkin, E.M., Hassin, R., Sviridenko, M.: Approximating the maximum quadratic assignment problem. Inf. Process. Lett. 77(1), 13–16 (2001).
https://doi.org/10.1016/S0020-0190(00)00151-4
4. Birkhoff, D.: Tres observaciones sobre el algebra lineal. Universidad Nacional de Tucuman Revista Serie A 5, 147–151 (1946)
5. Burkard, R.E., Çela, E., Pardalos, P.M., Pitsoulis, L.S.: The Quadratic Assignment Problem, pp. 1713–1809. Springer, Boston (1998).
https://doi.org/10.1007/978-1-4613-0303-9_27