John Collins Güleser K. Demir Maria L. Gini Bidtree Ordering in IDA* Combinatorial Auction Winner-Determination with Side Constraints. 17-33 2002 conf/amec/2002 AMEC http://link.springer.de/link/service/series/0558/bibs/2531/25310017.htm db/conf/amec/amec2002.html#CollinsDG02