Gravell90'

@inproceedings{DBLP:conf/zum/Gravell90,
  author    = {Andrew M. Gravell},
  title     = {What is a Good Formal Specification?},
  booktitle = {Z User Workshop},
  year      = {1990},
  pages     = {137-150},
  crossref  = {DBLP:conf/zum/1990},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}

@proceedings{DBLP:conf/zum/1990,
  editor    = {J. E. Nicholls},
  title     = {Z User Workshop, Oxford, UK, Proceedings of the Fifth Annual
               Z User Meeting, 17-18 December 1990},
  booktitle = {Z User Workshop},
  publisher = {Springer},
  series    = {Workshops in Computing},
  year      = {1991},
  isbn      = {3-540-19672-2},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}