Wang, Haoli, Xu, Xirong, Yuansheng, Yang, and Wang, Lei. “On the 3-γt-Critical Graphs of Order Δ(G) + 3”. Utilitas Mathematica 84 (May 9, 2011). Accessed May 8, 2026. https://utilitasmathematica.com/index.php/Index/article/view/802.