@article{Beeri83,
author = "C. Beeri and R. Fagin and D. Maier and  M.Yannakakis",
journal = "Journal of the ACM",
keywords = "bases de donnees, arbres, acyclicite",
pages = "479-513",
title = "{O}n the desirability of acyclic database schemes",
volume = "30",
year = "1983",
}