Мандрик, О. М., et al. “MULTIPLE-FACTOR ANALYSIS OF COMPLEX ENVIRONMENTAL TECHNICAL INSPECTION OF GAS-PUMPING UNIT UNDER DIFFERENT TECHNOLOGICAL OPERATION MODES”. Oil and Gas Power Engineering, no. 2(24), Nov. 2015, pp. 44-52, https://nge.nung.edu.ua/index.php/nge/article/view/345.