SCHALLER, H. W. Ljubenova, Lizbet: Petŭr Nikov. Žiznen pŭt i naučno delo. Südost-Forschungen, [S. l.], v. 1, n. 1, p. 492–493, 2021. Disponível em: http://bsb0sit-zepweb01.bsb.lrz.de/portal/index.php/sof/article/view/8980. Acesso em: 28 aug. 2024.