Musannaf Ibn Abi Shayba 13:2960

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Sharik narrated to us, from Jabir, from Salim, and al-Qasim, and Tawus, and Mujahid, and Muhammad ibn ‘Ali, and ‘Ata’: They said: There is no harm in a forward sale (salam) for silk.