References
==========

[1] M. Abrate, `Quadratic Formulas for Generalized Quaternions <http://www.worldscinet.com/jaa/08/0803/S0219498809003308.html>`_, The Journal of Algebra and its Applications, Vol. 8, Issue 3, pp. 289-306, 2009.

[2] M. Abrate, `The Roots of a Generalized Quaternion`, Congressus Numeratium, Vol. 201, Jan. 2010, 179-187 (Winnipeg, Canada)