Context-free multilanguages / Donald E. Knuth -- Proving nonmembership in certain families of context-free languages / Michael A. Harrison -- Single tree grammars / Sheila Greibach, Weiping Shi and Shai Simonson -- The complexity of structural containment and equivalence / D.J. Rosenkrantz and H.B. Hunt III -- The interface between language theory and database theory / Jeffrey D. Ullman -- Automata theory for database theoreticians / Moshe Y. Vardi -- On datalog linearization of chain queries / Guozhu Dong -- Expressive power of query languages / Serge Abiteboul and Victor Vianu -- Object identity and query equivalences / Richard Hull and Masatoshi Yoshikawa -- A unified approach to data and meta-data modification for data/knowledge bases / I-Min Amy Chen and Dennis McLeod -- Polygon clipping : analysis and experiences / Ellis Horowitz and Marco Papa.