@article{DBLP:journals/entcs/FokkinkP05a,
  author    = {Wan Fokkink and
               Jun Pang},
  title     = {Formal Verification of Timed Systems Using Cones and Foci},
  journal   = {Electr. Notes Theor. Comput. Sci.},
  volume    = {139},
  number    = {1},
  year      = {2005},
  pages     = {105-122},
  ee        = {http://dx.doi.org/10.1016/j.entcs.2005.09.003},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}