1. Abłamowicz R., Fauser B., Podlaski K., Rembielinski J.: Idempotents of Clifford algebras. Czechoslovak Journal of Physics 53(11), 949–954 (2003)
2. Altmann Simon L.: Rotations, Quaternions, and Double Groups. Oxford University Press, Oxford (1986)
3. Benno Artmann, The concept of number : from quaternions to monads and topological fields. Ellis Horwood series in mathematics and its applications. Ellis Horwood, Halsted, Chichester, 1988. Translation of: Der Zahlbegriff, Gottigen: Vandenhoeck & Rupprecht, 1983. Translated with additional exercises and material by H.B. Griffiths.
4. Borowski, E.J., Borwein, J.M., editors: Collins Dictionary of Mathematics. HarperCollins, Glasgow, 2nd edition, (2002)
5. Bouvier, Alain, George, Michel, Le Lionnais, Franois, editors: Dictionnaire des Mathmatiques. Quadrige/Puf, Paris, 2e edition, (2005)