NIELSEN, M.; ROZENBERG, G.; THIAGARAJAN, P. S. Elementary Transition Systems and Refinement. DAIMI Report Series, [S. l.], v. 20, n. 346, 1991. DOI: 10.7146/dpb.v20i346.6576. Disponível em: https://tidsskrift.dk/daimipb/article/view/6576. Acesso em: 9 may. 2024.