Brown87'

@article{DBLP:journals/isci/Brown87,
  author    = {Paul Walton Purdom Jr. and
               Cynthia A. Brown},
  title     = {Polynomial-average-time satisfiability problems},
  journal   = {Inf. Sci.},
  volume    = {41},
  number    = {1},
  year      = {1987},
  pages     = {23-42},
  ee        = {http://dx.doi.org/10.1016/0020-0255(87)90003-X},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}