Musannaf Ibn Abi Shayba 13:3288

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Sufyan, from Jabir, from ‘Amir, he said: He was asked about a man who buys cloth for such and such dinars, [with] the dinar at ten [dirhams]. He said: And Masruq narrated to me, from ‘Abdullah, he said: Two transactions in one transaction are not valid.