HELBIG, Gerhard. Probleme der Sprechakttheorie. Studia Germanica Posnaniensia, [S. l.], v. 9, p. 3–20, 2018. DOI: 10.14746/sgp.1980.09.01. Disponível em: https://pressto.amu.edu.pl/index.php/sgp/article/view/16174. Acesso em: 22 grudz. 2024.