KUO, Chung-Cheng; YEH, Nai-Sher. Multiplicative perturbations of local C-cosine functions. Studia Universitatis Babeș-Bolyai Mathematica, [S. l.], v. 66, n. 3, p. 575–589, 2021. DOI: 10.24193/subbmath.2021.3.13. Disponível em: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1373. Acesso em: 5 feb. 2025.