SACERDOTE, George S. On a Problem of Boone. Mathematica Scandinavica, Berkeley, CA, United States, v. 31, p. 111–117, 1972. DOI: 10.7146/math.scand.a-11417. Disponível em: https://journals.msp.org/mscand/article/view/2228. Acesso em: 25 jul. 2026.