Musannaf Ibn Abi Shayba 18:575

Abu Bakr narrated to us, he said: Hafs narrated to us, from Ash'ath, from Abu Bakr ibn Hafs, he said: I saw Ibn al-Zubayr exact retaliation for a *ma'muma* (a head wound that reaches the membrane covering the brain). He said: Then I saw them both walking, both having been wounded with a *ma'muma*.