Musannaf Ibn Abi Shayba 13:1451

Abu Bakr narrated to us, he said: Hushaym narrated to us, from Yahya ibn Sa'id, from al-Qasim, from Ibn 'Abbas, that he was asked about the *salam* (forward sale) of garments (*karabis*). He said: "There is no harm in it, if it is for a known measurement and for a known term."