@ARTICLE{dmp07B,
  author = {U. {Dal Lago} and A. Montanari and G. Puppis},
  title = {Compact and Tractable Automaton-based Representations for Time Granularities},
  journal = {Theoretical Computer Science},
  year = {2007},
  volume = {373},
  pages = {115-141},
  number = {1-2},
  publisher = {Elsevier Science Publishers Ltd.}
}