Yahya related to me from Malik from Ibn Shihab that Said ibn al-Musayyab used to say, "The full blood-money is payable for cutting offboth lips, but when the lower one only is cut off, two-thirds of theblood-money is due for it." (AR)
USC-MSA web (English) reference: Book 43, Hadith 6 (AR)
Arabic reference (AR): Book 43, Hadith 1567 (AR)