Musannaf Ibn Abi Shayba 13:3067

Abu Bakr narrated to us, he said: Abdullah ibn al-Mubarak narrated to us, from Ibn Jurayj, who said: I said to Ata, "I go to my regular customer and buy goods from him, and I pay him more than their price." He said, "If you wished, you could have taken them from him without that." I said, "I sell them to him on credit (mushaqqa)." He said, "No," meaning [it is not] murabaha (cost-plus profit sale).