Petkova, Petya. “TETRAHEDRAL COMPLEX OF Cr3+ AND Cr4+ IONS IN Bi12SiO20”.
JOURNAL SCIENTIFIC AND APPLIED RESEARCH
2, no. 1 (March 4, 2023): 58–65. Accessed April 10, 2025. https://jsar.ftn.shu.bg/index.php/jsar/article/view/44.