Sarah Zubair Mirza: ORAL TRADITION AND SCRIBAL CONVENTIONS IN THE DOCUMENTS ATTRIBUTED TO THE PROPHET MUḤAMMAD, A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Near Eastern Studies) in The University of Michigan, 2010, side 16f med referanse til Chase Robinson: Islamic Historiography – http://deepblue.lib.umich.edu/bitstream/2027.42/77783/1/smirza_1.pdf