A. Agogino, K. Tumer, and R. Miikkulainen. GECCO'05: Proc. 7th Genetic and Evolutionary Computation Conf., page 1309--1316. Washington, DC, ACM Press, (2005)
M. Khouadjia, E. Alba, L. Jourdan, and E. Talbi. Swarm Intelligence, volume 6234 of Lecture Notes in Computer Science, Springer, Berlin / Heidelberg, (2010)