Ishola, Abdullahi Saliu, et al. “Al‑‘aqd Al‑sahih: The Legal Basis for Determining the Validity of Islamic Financial Transactions”. International Journal of Economics and Financial Issues, vol. 6, no. 3S, June 2016, pp. 140-3, https://econjournals.com/index.php/ijefi/article/view/2622.