Source: https://www.researchgate.net/profile/Fathullah-Asni/publication/339096042_Socio-economics_and_management_of_Muslim_cemetery_waqf_using_istibdal_and_GIS_method_in_Penang_state/links/5f728115299bf1b53efc8c07/Socio-economics-and-management-of-Muslim-cemetery-waqf-using-istibdal-and-GIS-method-in-Penang-state.pdf