Susan Cholette Özgür Özlük Mahmut Parlar Optimal Keyword Bids in Search-Based Advertising with Stochastic Advertisement Positions. 225-244 2012 152 J. Optimization Theory and Applications 1 http://dx.doi.org/10.1007/s10957-011-9886-3 db/journals/jota/jota152.html#CholetteOP12