Hadith 10:770
Abu Bakr narrated to us, he said: Waki’ narrated to us, from Ali ibn Mubarak, from Yahya ibn Abi Kathir, from Abu Salamah and Thawban, they both said: "If he divorces her in his sitting, it is binding upon him, and if not, then it is not."
حدثنا أبو بكر قال نا وكيع عن علي بن مبارك عن يحيى بن أبي كثير عن أبي سلمة وبان ثوبان قالا إن طلقها في مجلسه لزمه وإلا فلا