Abdullah, M. M., and A. B. Awang. “Guidelines for the Application of Purchase (Bay’) and Loan (Salaf) in the Bank Letter of Guarantee: ضوابط تطبيقات بيع وسلف في خطاب الضمان المصرفي”. International Journal of Fiqh and Usul Al-Fiqh Studies, vol. 2, no. 2, Dec. 2018, pp. 124-36, doi:10.31436/ijfus.v2i2.103.