M ALI, Rosihan; SINGH, Vikramaditya. Pekali Dua Subkelas Fungsi Bak-Bintang. MATEMATIKA, [S. l.], v. 11, p. 73–85, 1995. DOI: 10.11113/matematika.v11.n.473. Disponível em: https://matematika.utm.my/index.php/matematika/article/view/473. Acesso em: 7 may. 2024.