Arnon Rosenthal, César A. Galindo-Legaria. Query Graphs, Implementing Trees, and Freely-Reorderable Outerjoins. In Hector Garcia-Molina, H. V. Jagadish, editors, Proceedings of the 1990 ACM SIGMOD International Conference on Management of Data, Atlantic City, NJ, May 23-25, 1990. pages 291-299, ACM Press, 1990. [doi]
Abstract is missing.