Nor Muhamad, Nasrul Hisyam. 2015. “’UMRA DAN RUQBA: ANALISIS MENGENAI KESANNYA TERHADAP KONTRAK HIBAH DAN POTENSINYA SEBAGAI INSTRUMEN AGIHAN HARTA: ’Umra and Ruqba: An Analysis of Their Impact on The Hibah Contract and Their Potential As Instruments of Wealth Distribution”. Jurnal Syariah 20 (1):1-46. https://ajap.um.edu.my/index.php/JS/article/view/22626.