SussmanS80'

@article{DBLP:journals/ai/SussmanS80,
  author    = {Gerald J. Sussman and
               Guy L. Steele Jr.},
  title     = {CONSTRAINTS - A Language for Expressing Almost-Hierarchical
               Descriptions},
  journal   = {Artif. Intell.},
  volume    = {14},
  number    = {1},
  year      = {1980},
  pages     = {1-39},
  ee        = {http://dx.doi.org/10.1016/0004-3702(80)90032-6},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}