1. Lecture Notes in Computer Science,1997
2. Best, E., Devillers, R.R., Hall, J.G.: The box calculus: a new causal algebra with multi-label communication. In: Rozenberg [19], pp. 21–69
3. Lecture Notes in Computer Science;G. Boudol,1987
4. Chothia, T., Klejin, J.: Q-automata: Modelling the resource usage of concurrent components. Electronic Notes in Theoretical Computer Science 175(175), 153–167 (2007)
5. Droste, M., Kuich, W.: Semirings and Formal Power Series. In: Droste, et al. (eds.) [6], ch.1, pp. 3–28 (2009)