KNUDSEN, F. F.; SEIP, K.; ULANOVSKII, A. M. A Best Covering Problem. Mathematica Scandinavica, Berkeley, CA, United States, v. 77, p. 272–280, 1995. DOI: 10.7146/math.scand.a-12565. Disponível em: https://journals.msp.org/mscand/article/view/1107. Acesso em: 25 jul. 2026.