ALLIGNOL, A.; SCHUMACHER, M.; BEYERSMANN, J. Empirical Transition Matrix of Multi-State Models: The etm Package. Journal of Statistical Software, [S. l.], v. 38, n. 4, p. 1–15, 2011. DOI: 10.18637/jss.v038.i04. Disponível em: https://www.jstatsoft.org/index.php/jss/article/view/v038i04. Acesso em: 28 may. 2022.