Al-kloub, Bashar. “Survey Of Productivity Measurement Techniques And Application To Five Major Natural Resources Industries In Jordan”. Al-Balqa Journal for Research and Studies 5, no. 1 (June 30, 1997): 61–84. Accessed October 11, 2026. https://ajrs.ammanu.edu.jo/ojs/index.php/albalqajournal/article/view/503.