SturmW01'

@article{DBLP:journals/jphil/SturmW01,
  author    = {Holger Sturm and
               Frank Wolter},
  title     = {First-order Expressivity for S5-models: Modal vs. Two-sorted
               Languages},
  journal   = {J. Philosophical Logic},
  volume    = {30},
  number    = {6},
  year      = {2001},
  pages     = {571-591},
  ee        = {http://dx.doi.org/10.1023/A:1013360121031},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}