Musannaf Ibn Abi Shayba 13:1763

Abu Bakr narrated to us, he said: Ibn Mahdi narrated to us, from Hammad ibn Salamah, from Ziyad al-A'lam, from al-Hasan, he said: If he sells it by *murabahah* (cost-plus profit), then the profit is upon the capital. And if he sells it by *musawamah* (bargaining), then it is between them in two halves. And from Qatadah is the like of that.