@inproceedings{DBLP:conf/icde/EichmannA91,
  author    = {David Eichmann and
               D. Alton},
  title     = {A Polymorphic Relational Algebra and Its Optimization},
  booktitle = {ICDE},
  year      = {1991},
  pages     = {680-689},
  ee        = {http://dx.doi.org/10.1109/ICDE.1991.131517},
  crossref  = {DBLP:conf/icde/91},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}

@proceedings{DBLP:conf/icde/91,
  title     = {Proceedings of the Seventh International Conference on Data
               Engineering, April 8-12, 1991, Kobe, Japan},
  publisher = {IEEE Computer Society},
  year      = {1991},
  isbn      = {0-8186-2138-9},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}