@article{TimpfVoltaPollocketal.1992,
  author    = {Sabine Timpf and Gary S. Volta and David W. Pollock and Max J. Egenhofer},
  title     = {A conceptual model of wayfinding using multiple levels of abstraction},
  journal   = {Lecture Notes in Computer Science},
  volume    = {639},
  pages     = {348 -- 367},
  doi       = {10.1007/3-540-55966-3_21},
  year      = {1992},
}