Kaushik, S. K., and Varinder Kumar. “$\mathcal{AD}$-Frames Satisfying Property $\mathcal{B}$”. Communications in Mathematics and Applications 3, no. 3 (December 26, 2012): 303–312. Accessed May 4, 2024. https://www.rgnpublications.com/journals/index.php/cma/article/view/214.