1. Ruiz Shulcloper, J., Adolfo Guzmán Arenas y J. Fco. Martínez Trinidad: Enfoque Lógico Combinatorio al Reconocimiento de Patrones, Editorial Politécnica (1999) ISBN: 970-18-2384-1
2. Pudil, P., Ferri, F.J., Novovièová, J., Kittler, J.: Floating Search Methods for Feature Selection with Nonmonotonic Criterion Functions. In: Proceedings of the 12th International Conference on Pattern Recognition, Jerusalem, Israel, pp. 279–283. IEEE Computer Society Press, Los Alamitos (1994)
3. Lazo-Cortes, M., Ruiz-Shulcloper, J., Alba-Cabrera, E.: An overview of the evolution of the concept of testor. Pattern Recognition 34(4), 753–762 (2001)
4. Machine Learning Databases, University of California, Irivne, Deparment of Information & Computation Science,
http://ftp.ics.uci.edu/pub/machine-learning-databases/
5. Cambridge, A.L.: Olivetti Research Laboratory face database,
http://www.uk.research.att.com/facedatabase.html