Álvarez Paiva, J. C. (2006), "Some problems on Finsler geometry", Handbook of differential geometry. Vol. II, Elsevier/North-Holland, Amsterdam, pp. 1–33, doi:10.1016/S1874-5741(06)80004-X, MR2194667. See in particular p. 16.
Harrell, R. E.; Karlovitz, L. A. (1970), "Girths and flat Banach spaces", Bulletin of the American Mathematical Society, 76 (6): 1288–1291, doi:10.1090/S0002-9904-1970-12643-X, MR0267383.
Álvarez Paiva, J. C. (2006), "Some problems on Finsler geometry", Handbook of differential geometry. Vol. II, Elsevier/North-Holland, Amsterdam, pp. 1–33, doi:10.1016/S1874-5741(06)80004-X, MR2194667. See in particular p. 16.
Álvarez Paiva, J. C. (2006), "Some problems on Finsler geometry", Handbook of differential geometry. Vol. II, Elsevier/North-Holland, Amsterdam, pp. 1–33, doi:10.1016/S1874-5741(06)80004-X, MR2194667. See in particular p. 16.
Harrell, R. E.; Karlovitz, L. A. (1970), "Girths and flat Banach spaces", Bulletin of the American Mathematical Society, 76 (6): 1288–1291, doi:10.1090/S0002-9904-1970-12643-X, MR0267383.