Musnad Ahmad 1153:1378

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Muhammad ibn 'Abd al-Rahman al-Ansari, from his paternal aunt 'Amrah, from 'Aishah, that she said: "When the dawn broke, the Messenger of Allah (peace and blessings of Allah be upon him) would pray two rak'ahs—or he would not pray except two rak'ahs." I say: Does he recite in them the Opening of the Book (Al-Fatihah)?