Sunan Abi Dawud 1361
سنن أبي داود#1361SahihNarrated 'Aishah: The Messenger of Allah (ﷺ) offered the night prayer and then prayed eight rak'ahs standing, and two rak'ahs between the two adhans (i.e. the adhan for the dawn prayer and the iqamah). He never left them. Jaf'ar b. Musafir said in his version: (He prayed) the two rak'ahs sitting between the two adhans. He added the word "sitting
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Bukhari (1159)
In-book reference: 5:112