@article{DBLP:journals/tse/Bradley88,
  author    = {J. Bradley},
  title     = {A Group-Select Operation for Relational Algebra and Implications
               for Database Machine Design},
  journal   = {IEEE Trans. Software Eng.},
  volume    = {14},
  number    = {1},
  year      = {1988},
  pages     = {126-129},
  ee        = {http://doi.ieeecomputersociety.org/10.1109/32.4630},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}