@article{GolMatVai:96,
  journal = {J. Autom. Lang. Comb.},
  volume = {1},
  title = {Semirings and parallel composition of processes},
  year = {1996},
  fjournal = {Journal of Automata, Languages and Combinatorics},
  pages = {199--217},
  number = {3},
  author = {Golan, Jonathan S. and Mateescu, Alexandru and Vaida, Dragos},
}