T. Zhang, R. Ramakrishnan, и M. Livny. Proceedings of the 1996 ACM SIGMOD international conference on Management
of Data (SIGMOD'96), стр. 103--114. ACM Press, (июня 1996)
C. Zhou. WCSE '09: Proceedings of the 2009 WRI World Congress on Software Engineering, стр. 155--159. Washington, DC, USA, IEEE Computer Society, (2009)