BUSEMANN, Herbert. Convex Bodies and Convexity on Grassmann Cones XI. Sublinear Functions. Mathematica Scandinavica, Berkeley, CA, United States, v. 24, p. 93–101, 1969. DOI: 10.7146/math.scand.a-10922. Disponível em: https://journals.msp.org/mscand/article/view/2375. Acesso em: 25 jul. 2026.