Richard C. H. Connor Alberto O. Mendelzon Research Issues in Structured and Semistructured Database Programming, 7th International Workshop on Database Programming Languages, DBPL'99, Kinloch Rannoch, Scotland, UK, September 1-3, 1999, Revised Papers DBPL Lecture Notes in Computer Science 1949 Springer 2000 3-540-41481-9 db/conf/dbpl/dbpl1999.html