@article{da silveira_combacau_2006,  title={Supervision and control of heterarchical discrete event systems},  volume={17},  ISSN={0103-1759},  url={https://doi.org/10.1590/S0103-17592006000100001},  DOI={10.1590/S0103-17592006000100001},  number={1},  journal={Sba: Controle & Automação Sociedade Brasileira de Automatica},  publisher={Sociedade Brasileira de Automática},  author={Da Silveira, Marcos R. and Combacau, Michel},  year={2006},  month={Jan},  pages={1–9} }