Musnad Ahmad 1153:151

Isma'il narrated to us, Ayyub informed us, from Abu al-Zubayr, from 'Ubayd ibn 'Umayr, who said: It reached 'Aishah that 'Abdullah ibn 'Amr commands women, when they perform ghusl (ritual bath), to undo their hair. She said: "How strange of Ibn 'Amr! He commands women, when they perform ghusl, to undo their hair. Why does he not command them to shave it? I used to perform ghusl with the Messenger of Allah, peace and blessings of Allah be upon him, from a single vessel, and I would do no more than pour three handfuls of water over my head."