V. SUBPRABHA; P. T. INFANT VIJULA; N. DURGA DEVI. New forms of open and closed sets using $(1,2) S_\beta$-open sets in bitopological spaces. Malaya Journal of Matematik, India, v. 9, n. 01, p. 1040–1042, 2021. Disponível em: https://www.malayajournal.org/index.php/mjm/article/view/1214. Acesso em: 16 jul. 2024.