CHUVAEV, K.K.; OKNYANSKIJ, V.L.; LYUTY, V.M. Optical variability of NGC 4151 during past 100 years . Известия Крымской астрофизической обсерватории, [S. l.], v. 104, n. 3, p. 109–113, 2008. Disponível em: https://jncrao.ru/index.php/izvcrao/article/view/754. Acesso em: 20 фев. 2026.