Musnad Ahmad 32:1800

Husayn narrated to us, Shu'bah narrated to us, from Abdullah ibn al-Mukhtar, who said: I heard Musa ibn Anas—he said: And perhaps we would sit with him, I and he, he said: And he was among our youths, younger than me in age—narrating from Anas: "That the Prophet, peace and blessings of Allah be upon him, led Anas and a woman in prayer, so he placed Anas to his right, and the woman behind them."