1. Barland, I., Kolaitis, P., Vardi, M., & Felleisen, M. (2011). Propositional logic: normal forms. Connexions. Retrieved January 14, 2011, from http://cnx.org/content/ m12075/1.12/
2. Cook, S. A. (1971). The complexity of theorem-proving procedures. In Proceedings of the Third Annual ACM Symposium on Theory of Computing (pp. 151-158). New York, NY: ACM.
3. Efficient lower bounds and heuristics for the variable cost and size bin packing problem
4. Cruz-Reyes, L., Gómez, C. G., Hernández, I. Y., Rangel, N., Álvarez, V. M., & González, J. J. (2008). An architecture for selecting data distribution algorithms. In Proceeding of the 17th International Multi-conference on Advanced Computer Systems (pp. 19-25).