Umm Musa says that I asked Hazrat Aisha (may Allah be pleased with her) about the two rak'ahs after Asr, so she replied that whenever the Prophet (peace be upon him) came to me, he definitely performed two rak'ahs after Asr.
Hadith Referenceمسند احمد / مسند النساء / 24783
Hadith Gradingحکم دارالسلام:حديث صحيح، أم موسي توبعت