Ostapenko, Olga, і Olena Bakum. «ECONOMIC EFFICIENCY OF HEAT-PUMPING STATIONS ON THE CONDITIONS OF FUEL AND ENERGY RESOURCES COST CHANGE AND VARIABLE OPERATION MODES». Scientific Works of Vinnytsia National Technical University, no. 1 (Листопад 25, 2015). дата звернення Квітень 27, 2026. https://works.vntu.edu.ua/index.php/works/article/view/406.