Tee, Elok Robert, A.K. Ramani, and S. Selvakennedy. 1997. “A Token-Passing Variable Buffer Model For A Double-Layered Hierarchical WDM All-Optical Network”. Malaysian Journal of Computer Science 11 (1):41-50. https://ijie.um.edu.my/index.php/MJCS/article/view/3215.