Musannaf Ibn Abi Shayba 18:773

Abu Bakr narrated to us, he said: Ali bin Mushir narrated to us, from Hisham, from al-Sha’bi, from Shurayh, that Hisham bin Hubayra wrote to him asking him, so he wrote back to him: "The blood money (diyah) of a woman is half of the blood money of a man, in both small and large matters." And Ibn Mas’ud used to say regarding the blood money of a woman in cases of error: "It is half of the blood money of a man, except for the tooth and the *mudihah* (a wound that exposes the bone), for in those two, they are equal." And Zayd bin Thabit used to say: "The blood money of a woman in cases of error is like the blood money of a man until it reaches one-third of the blood money; whatever exceeds that, it is half."