@article{DBLP:journals/tcs/GyssensG91,
author = {Marc Gyssens and
Dirk Van Gucht},
title = {A Comparison between Algebraic Query Languages for Flat
and Nested Databases},
journal = {Theor. Comput. Sci.},
volume = {87},
number = {2},
year = {1991},
pages = {263-286},
ee = {http://dx.doi.org/10.1016/0304-3975(91)90327-X},
bibsource = {DBLP, http://dblp.uni-trier.de}
}