GRIGELIONIS , B. On the excessive functions of the step Markov processes and optimal stopping rules. Lithuanian Mathematical Journal, [S. l.], v. 7, n. 1, p. 37–44, 1967. DOI: 10.15388/LMJ.1967.19932. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19932. Acesso em: 28 apr. 2025.