1. H. S. M. Coxeter, Introduction to Geometry, John Wiley & Sons, New York, 5th Printing, 1966.
2. D. Gans, Transformations and Geometries, Appleton-Century-Crofts, New York, 1969.
3. M. J. Greenberg, Euclidean and Non-Euclidean Geometries, 2nd ed., W. H. Freeman and Company, San Francisco, 1980.
4. Absolute Polarities and Central Inversions