Musnad Ahmad 1153:179

Abu Mu’awiyah narrated to us, Al-A’mash narrated to us, from Muslim, from Masruq, from ‘Aishah. And Ibn Ja’far narrated to us, Shu’bah narrated to us, from Sulayman, who said: I heard Abu al-Duha, from Masruq, from ‘Aishah, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, performed the Witr prayer during every part of the night, and his Witr ended at the time of the dawn (al-sahar)."