Lenkova, O. V., A. S. Permyakov, O. G. Yakunina, and M. V. Vechkasova. “Problems and Prospects of Innovative Development of Petrochemical Enterprises”. International Journal of Energy Economics and Policy, vol. 7, no. 3, July 2017, pp. 321-5, https://econjournals.com/index.php/ijeep/article/view/5115.