1. H. S. M. Coxeter and W. O. J. Moser, Generators and Relations for Discrete Groups, 3rd ed., Springer-Verlag, 1972, sect. 4.2 and Table 2.
2. E. H. Gombrich, The Sense of Order: A Study in the Psychology of Decorative Art, Cornell University Press, Ithaca, 1979.
3. B. Grünbaum, Color symmetries and colored patterns, dittoed notes, University of Washington, Seattle, 1976. (See also [5]).
4. Patterns on the 2‐Sphere