Claire David, Leonid Libkin, Filip Murlak. Certain answers for XML queries. In Jan Paredaens, Dirk Van Gucht, editors, Proceedings of the Twenty-Ninth ACM SIGMOD-SIGACT-SIGART Symposium on Principles of Database Systems, PODS 2010, June 6-11, 2010, Indianapolis, Indiana, USA. pages 191-202, ACM, 2010. [doi]
Abstract is missing.