Tungatarova, S., and M. Zhumabek. “Synthesis of Olefins and Oxygen Containing Mixtures from C3–C4 Alkanes”. Chemical Bulletin of Kazakh National University, Vol. 61, no. 1, Mar. 2011, pp. 107-12, https://chemistry.kz/bulletin/index.php/kaznu/article/view/861.