Sahih Muslim 57:22

Amr an-Nāqid narrated to us, Sufyān bin Uyaynah narrated to us, on authority of Hishām bin Hujayr, on authority of Tāwus, he said:

‘A book was brought to Ibn Abbās which contained the verdicts of Alī, may Allah be pleased with him, and he effaced but a small amount,’ and Sufyān bin Uyaynah indicated with his arm [the amount].