JÓNSSON, Bjarni; MCKENZIE, Ralph. Powers of partially ordered sets: Cancellation and reffinement properties. Mathematica Scandinavica, Berkeley, CA, United States, v. 51, p. 87–120, 1982. DOI: 10.7146/math.scand.a-11966. Disponível em: https://journals.msp.org/mscand/article/view/1682. Acesso em: 25 jul. 2026.