Sunan an-Nasa'i 685

It was narrated that 'Aishah said:"Between the time when he finished 'Isha' prayer and Fajr, the Prophet (S.A.W) used to pray eleven Rak'ahs, saying the Taslim after each two Rak'ahs, then praying Witr as one Rak'ah. He would prostrate for as long as it takes one of you to recite fifty verses, then he would raise his head. When the Mu'adhdhin finished the call to Fajr prayer and he could see the dawn, he would pray two brief Rak'ahs, then he would go out with him." Some of these narrators (Ibn Abi Dhi'b, Yunus and 'Amr bin Al-Harith) added some phrases not mentioned by the others in the Hadith