FALAHATI-NEZHAD, Farzaneh, and Mahdieh AZARI. “THE INVERSE SUM INDEG INDEX OF SOME NANOTUBES”. Studia Universitatis Babeș-Bolyai Chemia, vol. 61, no. 1, Mar. 2016, pp. 63-70, https://studia.reviste.ubbcluj.ro/index.php/chemia/article/view/8280.