BUSEMANN, Herbert; PEDERSEN, Flemming P. Tori with one-parameter groups of motions. Mathematica Scandinavica, Berkeley, CA, United States, v. 3, p. 209–220, 1955. DOI: 10.7146/math.scand.a-10438. Disponível em: https://journals.msp.org/mscand/article/view/2886. Acesso em: 8 sep. 2026.