Sunan an-Nasa'i, Volume 1, Book 6, Hadith 577 (DarusSalam) ⓘ
It was narrated that Abu Ishaq said: "I heard Masruq and Al-Aswad say: We bear witness that 'Aishah said: 'When the Messenger of Allah was with me after 'Asr, he would pray them (these two Rak'ahs).'"
أَخْبَرَنَا إِسْمَاعِيلُ بْنُ مَسْعُودٍ، عَنْ خَالِدِ بْنِ الْحَارِثِ، عَنْ شُعْبَةَ، عَنْ أَبِي إِسْحَاقَ، قَالَ سَمِعْتُ مَسْرُوقًا، وَالأَسْوَدَ، قَالاَ نَشْهَدُ عَلَى عَائِشَةَ أَنَّهَا قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا كَانَ عِنْدِي بَعْدَ الْعَصْرِ صَلاَّهُمَا .
also referenced under: Book 6, Hadith 583 (In-Book)