Musannaf Ibn Abi Shayba 13:454

Abu Bakr narrated to us, he said: Yazid ibn Harun narrated to us, from Abd al-Malik, from Ata, regarding a man who sells by *murabaha* (cost-plus profit) and takes a profit for the transport cost: He said: He may take a profit on what was spent in the land from which he departed, if he wishes. As for what was spent in the town in which he sold, he shall not take a profit [on it].