Sunan Ibn Majah
1186
Hasan Sahih+2

It was narrated that ‘Ali said:“At every part of the night the Messenger of Allah (ﷺ) prayed Witr, at the beginning and in the middle, and finally his Witr was just before dawn.”

Hasan SahihAl-Albani
Hasan SahihMuhammad Fouad Abd al-Baqi