R. Colini-Baldeschi, S. Leonardi, M. H. Henzinger, and M. Starnberger, “On multiple keyword sponsored search auctions with budgets,” ACM Transactions on Economics and Computation, vol. 4, no. 1. Association for Computing Machinery, 2015.
LibreCat: https://research-explorer.ista.ac.at/record/11668
DOI: 10.1145/2818357