BUSEMANN, Herbert. Planes with analogues to Euclidean angular bisectors. Mathematica Scandinavica, Berkeley, CA, United States, v. 36, p. 5–11, 1975. DOI: 10.7146/math.scand.a-11556. Disponível em: https://journals.msp.org/mscand/article/view/2059. Acesso em: 25 jul. 2026.