References
J. J. Gray
(1992). Poincaré and Klein: groups and geometries. In L. Boi, D. Flament & J. Salanskis (eds.) 1830–1930: a century of geometry (pp. 35-44). Dordrecht: Springer.
(1992). Poincaré and Klein: groups and geometries. In L. Boi, D. Flament & J. Salanskis (eds.) 1830–1930: a century of geometry (pp. 35-44). Dordrecht: Springer.