Musnad Ahmad 32:1171

Yazid narrated to us, Hammam ibn Yahya informed us, Abu Ghalib al-Khayyat narrated to us, he said: I witnessed Anas ibn Malik pray over the funeral of a man, and he stood at his head. When it was lifted, the funeral of a woman from the Quraysh or the Ansar was brought, and it was said to him: "O Abu Hamzah, this is the funeral of so-and-so, daughter of so-and-so, so pray over her." He prayed over her, and he stood at her middle. Among us was al-Ala’ ibn Ziyad al-Adawi. When he saw the difference in his standing for the man and the woman, he said: "O Abu Hamzah, is this how the Messenger of Allah (peace and blessings of Allah be upon him) used to do? He would stand for the man where you stood, and for the woman where you stood?" He said: "Yes." He said: Then al-Ala’ turned to us and said: "Memorize this."