Aisha Y. Musa, Hadith as scripture: discussions on the authority of prophetic traditions in Islam, Macmillan, 2008, ISBN 978-0-230-60535-0.
«... authorship of the Risala and Kitab al-Umm, he accepts that 'the Shafi'i school was ahead of other schools in devising hermeneutic arguments that would assure the accommodation of the law to a growing set of Prophetic hadith' ...»
