1. Non first normal form relations to represent hierarchically organized data;Abiteboul,1984
2. Database theory column: query languages for complex object databases;Abiteboul;SIGACT News,1990
3. Concepts for graph-oriented object manipulation;Andries,1991
4. Proceedings EDBT'92,1992
5. The New Oxford English Dictionary project at the University of Waterloo;Berg,1991