Musnad Abu Ya'la al-Mawsili 217:6

Muhammad ibn Qudamah narrated to us, Sufyan ibn 'Uyaynah narrated to us, he said: Al-Shaybani narrated to me, from 'Abdullah ibn Shaddad, from Maymunah: That the Prophet, peace and blessings of Allah be upon him, prayed in a garment (mirṭ), part of which was upon him and part of which was upon her, while she was menstruating.