Musannaf Ibn Abi Shayba 24:180

Abu Sufyan al-Himyari narrated to us, he said: Khalid bin Muhammad al-Qurashi narrated to us, he said: Abd al-Malik bin Marwan said: "Whoever wants to take a slave girl for pleasure, let him take a Berber one. Whoever wants to take one for children, let him take a Persian one. Whoever wants to take one for service, let him take a Roman one."