´Aishah narrated:` "The night prayer of Allah's Messenger was thirteen Rak'ah, five of which were his Witr, not sitting in any of them except at the end of them. When the Mu'adh-dhin called the Adhan he would stand to perform two light (Rak'ah)."
Hadith Referenceسنن ترمذي / أبواب الوتر / 459
Hadith Gradingالألبانی:صحيح، صحيح أبي داود (1209 و 1210) ، صلاة التراويح | زبیر علی زئی:(459) إسناده ضعيف, الحارث الأعور ضعيف (تقدم:282) وأبو اسحاق عنعن (تقدم:107)