1. G. Chrystal, Textbook of Algebra (part one), Dover Publications, New York, 1961, 151–159.
2. G. Strang, Linear Algebra and its Applications, 2nd ed., Academic Press, New York, 1980.
3. B. L. van der Waerden, Modern Algebra (English trans, by Fred Blum), Frederich Ungar Publishing, New York, 1949, 88–90.