Biografi Khalifah Rasulullah : Abu Bakar, Umar, Utsman,Ali & Umar Bin Abdul Aziz / Khalid Muhammad Khalid Tim Penerjemah Ummul Qura Tim Editor Ummul Qura text Jakarta : Ummul Qura, 2016 ind Judul asli : Khulafour Rasul Khalifah Islam URN:ISBN:978-602-7637-17-7