PUPPEL, Stanisław. Some notes on ecophonetics: the problem of sound distinctiveness, sound sustainability, and the sustainability of vowel systems in contact conditions as exemplified by the standard Polish vowel system in contact with the Kashubian vowel system. Studia Germanica Posnaniensia, [S. l.], n. 38, p. 143–150, 2018. DOI: 10.14746/sgp.2017.38.12. Disponível em: https://pressto.amu.edu.pl/index.php/sgp/article/view/13176. Acesso em: 4 mar. 2024.