Daniel Richardson, John Fitch: The identity problem for elementary functions and constants. In: Proceedings of the international symposium on Symbolic and algebraic computation. ACM, 1994, S.285–290, doi:10.1145/190347.190429.
Jihun Yu, Chee Yap, Zilin Du, Sylvain Pion und Hervé Brönnimann: The Design of Core 2: A Library for Exact Numeric Computation in Geometry and Algebra. In: International Congress on Mathematical Software. Band3. Springer, 2010, S.121–141 (online [PDF; 305kB; abgerufen am 7. September 2012]). S. 4.
psu.edu
citeseerx.ist.psu.edu
Ioannis Z. Emiris und Elias P. Tsigaridas: Comparison Of Fourth-Degree Algebraic Numbers And Applications To Geometric Predicates. 2000 (online [abgerufen am 7. September 2012]).