Sarjono, Haryadi. “Metode Perhitungan Angka Indeks Produktivitas Menggunakan Model Marvin E Mundel”. Journal The Winners 2, no. 1 (March 31, 2001): 18-24. Accessed July 18, 2024. https://journal.binus.ac.id/index.php/winners/article/view/3797.