Ostapenko, O., і O. 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, вип. 1, Листопад 2015, https://works.vntu.edu.ua/index.php/works/article/view/406.