Abdul Khir, M. F., and R. Ahmad. “KONSEP NILAI MASA WANG DARIPADA PERSPEKTIF SYARIAH: SUATU SOROTAN KRITIKAL: The Concept of Time Value of Money From Shariah Perspective: A Critical Review”. Jurnal Syariah, vol. 19, no. 2, May 2011, pp. 107-32, http://adum.um.edu.my/index.php/JS/article/view/22636.