ACETO, L.; FOKKINK, W. J.; INGÓLFSDÓTTIR, A. A Cancellation Theorem for BCCSP. BRICS Report Series, [S. l.], v. 14, n. 17, 2007. DOI: 10.7146/brics.v14i17.22180. Disponível em: https://tidsskrift.dk/brics/article/view/22180. Acesso em: 29 nov. 2022.