Musnad Ahmad 1153:1441

'Abd al-Rahman and 'Affan narrated to us, they said: Hammad ibn Salamah narrated to us, from al-Azraq ibn Qays, he said: 'Affan said: Al-Azraq ibn Qays informed us, from Dhakwan, from 'Aishah: "That the Messenger of Allah, peace and blessings of Allah be upon him, used to pray on the khumrah (a small prayer mat made of palm leaves)."