Sahih Muslim Book 9, Hadith Number 3529.

Chapter: There is no maintenance allowance for one who has been given irrevocable divorce.

Abu Bakr reported: I and Abu Salama came to Fatima bint Qais (Allah be pleased with her) during the time of Ibn Zubair (Allah be pleased with him) and she narrated to us that her husband gave her an irrevocable divorce. (The rest of the hadith is the same.)