SCHIFFER, M.; TAMMI, O. On the fourth coefficient of univalent functions with bounded boundary rotation. Annales Fennici Mathematici, [S. l.], n. 396, 1967. DOI: 10.5186/aasfm.1967.396. Disponível em: https://afm.journal.fi/article/view/134072. Acesso em: 1 apr. 2026.