WINARTO, W.; KAMID, A.; RAMADHAN, A. Perhitungan Efisiensi Hydraulic Pumping Unit (HPU) pada Sumur yang Menggunakan Working Barrel Tipe Tubing Heavy Wall Barrel Mechanical PT. Pertamina Ep Cepu Regional 4 Zona 11 Cepu Field. Ranah Research : Journal of Multidisciplinary Research and Development, v. 7, n. 3, p. 2217-2229, 29 Mar. 2025.