Кафка, С. М., and О. С. Степанюк. “Formation of Cost Management System of Oil and Gas Extraction Enterprises”. Scientific Bulletin of Ivano-Frankivsk National Technical University of Oil and Gas (Series: Economics and Management in the Oil and Gas Industry), vol. 2, no. 12, Sept. 2015, pp. 36-45, https://eung.nung.edu.ua/index.php/ecom/article/view/113.