Hoang Kha, H., Nguyen, X.-X., Vo, K.T. and Quoc Hung, D. 2024. Spectral Efficiency for Active IRS-Aided Multi-Group Multicast Cognitive Radio Systems. VNUHCM Journal of Engineering and Technology. 7, 4 (Dec. 2024), In press. DOI:https://doi.org/https://doi.org/10.32508/stdjet.v7i4.1390.