Sheikholeslami, Seyed Mahmoud, Nasrin Dehgardi, Lutz Volkmann, and Dirk Meierling. “The Roman Bondage Number of a Digraph”. Tamkang Journal of Mathematics 47, no. 4 (December 30, 2016): 421–431. Accessed March 29, 2024. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/2100.