Musannaf Ibn Abi Shayba 19:715

Abu Bakr narrated to us, he said: Sharik ibn Abdullah narrated to us, from Firas, from Amir, from Masruq, from Ubayy, who said: "When two unmarried people commit adultery, they are to be flogged and banished. And when two married people commit adultery, they are to be flogged and stoned."