CIBULSKYTĖ, A. Ober Verteilung der Basiselementen in den freien Zahlenhalbgruppen. II. Lithuanian Mathematical Journal, [S. l.], v. 10, n. 3, p. 593–610, 1970. DOI: 10.15388/LMJ.1970.20908. Disponível em: https://www.zurnalai.vu.lt/LMJ/article/view/20908. Acesso em: 8 jun. 2025.