Sulaiman, Ahmad Azam, Mohd Sollehudin Shuib, and Mohammad Taqiuddin Mohamad. 2009. “Pembangunan Modal Manusia: Kajian Terhadap Pulangan Negara-Negara Islam Terpilih”. The Journal of Muamalat and Islamic Finance Research 6 (1):177-92. https://jmifr.usim.edu.my/index.php/jmifr/article/view/94.