Musnad Ahmad 26:753

Yahya ibn Zakariyya narrated to us, he said: Hajjaj narrated to us, from Zayd ibn Jubayr, from Khashf ibn Malik, from Ibn Mas’ud, who said: "The Messenger of Allah, may Allah bless him and grant him peace, decreed regarding the blood money for accidental killing: twenty female camels in their second year (bint makhad), twenty male camels in their second year (ibn makhad), twenty female camels in their third year (bint labun), twenty female camels in their fourth year (hiqqah), and twenty female camels in their fifth year (jadha’ah)."