Kaleidoscopes: Selected Writings of H. S. M. Coxeter, edited by F. Arthur Sherk, Peter McMullen, Anthony C. Thompson, Asia Ivic Weiss, Wiley-Interscience Publication, 1995, ISBN 978-0-471-01003-6[1] (页面存档备份,存于互联网档案馆) (Definition: paper 13, Discrete groups generated by reflections, 1933, p. 161)
Kaleidoscopes: Selected Writings of H. S. M. Coxeter, edited by F. Arthur Sherk, Peter McMullen, Anthony C. Thompson, Asia Ivic Weiss, Wiley-Interscience Publication, 1995, ISBN 978-0-471-01003-6[1] (页面存档备份,存于互联网档案馆) (Definition: paper 13, Discrete groups generated by reflections, 1933, p. 161)