Musannaf Ibn Abi Shayba 13:610

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Ja’far ibn Mihran, from Maymun, that ‘Aisha said to a *mukātab* (a slave under a contract of manumission) of hers, whose *kunyah* was Abu Maryam: "Enter, even if there remains upon you only four dirhams."