Musnad Abu Ya'la al-Mawsili 153:25

Abu Khaythama narrated to us, Waki' narrated to us, from Ibn Abi Dhi'b, from al-Zuhri, from Salim, from his father: That the Prophet, peace and blessings of Allah be upon him, combined the two of them at al-Muzdalifah. He prayed each one of them with an iqamah, and he did not perform any voluntary prayer before either of them, nor after them.