Musnad Ahmad 30:2003

Yunus narrated to us, Aban—meaning al-Attar—narrated to us, from Yahya, from Abu Salamah ibn Abd al-Rahman, from Abu Hurairah, that the Prophet of Allah, peace and blessings of Allah be upon him, forbade that a woman be married [at the same time] as her paternal aunt, or as her maternal aunt.