CICHY, Stefan; ZIMOŃ, Damian; RAK, Romuald. Problem der Improvisation in der Liturgie. Silesian Historical and Theological Studies, [S. l.], v. 11, p. 62–74, 1978. Disponível em: https://journals.us.edu.pl/index.php/ssht/article/view/22152. Acesso em: 10 nov. 2026.