سنن أبي داود

Narrated 'Aishah: Between the time when the Messenger of Allah (ﷺ) finished the night prayer till the dawn broke, he used to pray eleven rak'ahs, uttering the salutation at the end of every two and observing the witr with a single one, and during that he would make a prostration about as long a one of you would take to recite fifty verses before raising his head. When the mu'adhdhin finished making the call for the dawn prayer, he stood up and prayed two short rak'ahs, then he lay down on his right side till the mu'adhdhin came to him