Jingqiao Zhang Viswanath Avasarala Arthur C. Sanderson Tracy Mullen Differential evolution for discrete optimization: An experimental study on Combinatorial Auction problems. 2794-2800 2008 IEEE Congress on Evolutionary Computation http://dx.doi.org/10.1109/CEC.2008.4631173 conf/cec/2008 db/conf/cec/cec2008.html#ZhangASM08