Musnad Ahmad 1153:411

Abu Tamila Yahya ibn Wadih narrated to us, saying: "My father informed me, saying: 'I saw Abu Uthman Amr ibn Sulaym judging at his door.'" My father said: "And he is the one from whom Mahdi ibn Maymun narrated, and from whom Mutarrif ibn Tarif, Rabi ibn Sabih, and Layth ibn Abi Sulaym narrated."