Petkova, P., Vasilev, P. and Nedelcheva, G. 2023. THE COMPLEXES OF Co2+ IN Bi12SiO20 AND Co3+ IN Bi12TiO20. JOURNAL SCIENTIFIC AND APPLIED RESEARCH. 3, 1 (Mar. 2023), 78–83. DOI:https://doi.org/10.46687/jsar.v3i1.67.