Musannaf Ibn Abi Shayba 13:490

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Sufyan narrated to us, from Abu al-Wazi’, he said: I heard Ibn ‘Umar saying: "Who will sell me one camel for two camels? And who will sell me one she-camel for two she-camels?"