Phong, Đào N., N. X. Hoài, N. T. Thủy, and N. Q. Uy. “An Investigation of Genetic Programming for Q-Function Approximation”. Journal of Computer Science and Cybernetics, vol. 27, no. 4, May 2012, pp. 317-28, doi:10.15625/1813-9663/27/4/596.