Musnad Abu Ya'la al-Mawsili 150:306

'Abd al-Wahid ibn Ghiyath narrated to us, Abu 'Awanah narrated to us, from Mansur, from Ibrahim, from al-Aswad, from 'Aishah, who said: The Prophet, peace and blessings of Allah be upon him, used to command one of us, when she was menstruating, to wear an izar (a lower garment), then he would have physical contact with her.