JÓNSSON, Thórdur. Comparision of the length of infinite geodesics in manifolds with nonpositive curvature. Mathematica Scandinavica, Berkeley, CA, United States, v. 51, p. 151–157, 1982. DOI: 10.7146/math.scand.a-11969. Disponível em: https://journals.msp.org/mscand/article/view/1679. Acesso em: 25 jul. 2026.