Musnad Abu Ya'la al-Mawsili 155:285

Abu Musa narrated to us, Umar ibn Abi Khalifah narrated to us, from Muhammad ibn Amr, from Abu Salamah, from Abu Hurairah: That the Messenger of Allah (peace be upon him), when he intended to go on a journey, would cast lots among his wives. The lot fell to Aisha in the expedition of Banu al-Mustaliq.