Zobair, Mian Muhammad, Shaker, Hani, Imran, Muhammad, and Rehman, Noor. “Polynomial Structure of Benzene Ring Embedded in Periodic-Type Surface in 2-Dimension”. Utilitas Mathematica, vol. 108, Sept. 2018, https://utilitasmathematica.com/index.php/Index/article/view/1286.