Musnad Abu Ya'la al-Mawsili 150:73

Ja'far ibn Mihran narrated to us, 'Abd al-A'la narrated to us, Muhammad ibn Ishaq narrated to us, Muhammad ibn Ja'far ibn al-Zubayr narrated to me, from 'Urwah, from 'Aishah, who said: When I wanted to part the hair of the Messenger of Allah, I would make the parting from the crown of his head and let his forelock fall between his shoulders.