Musannaf Ibn Abi Shayba 16:393

Abu Abd al-Rahman Baqi ibn Makhlad narrated to us, he said: Abu Bakr Abdullah ibn Muhammad ibn Abi Shayba narrated to us, he said: Isma'il ibn 'Ulayya narrated to us, from Yahya ibn Abi Ishaq, who said: I saw upon Anas ibn Malik a garment of silk (khazz), and I saw upon al-Qasim a garment of silk (khazz), and I saw upon Ubayd Allah ibn Abdullah silk (khazz).