Ambarwati, Lasmini, Amelia K Indraistuti, and Pretiwindya Kusumawardhani. “Estimating the Value of Time and Its Application”. Open Science Journal 2, no. 2 (June 21, 2017). Accessed October 30, 2025. https://www.osjournal.org/ojs/index.php/OSJ/article/view/639.