Muwatta Malik (Yahya)

Imam Malik, may Allah have mercy on him, said: If a man says to his wife: "You are Khaliyyah (released)," or "Bariyyah (free)," or "Bainah (separated)," then if he has had intercourse with that woman, three divorces will take effect. And if he has not had intercourse, then it will be according to his intention. If he says: "I intended only one," then he will be considered truthful upon taking an oath. However, the woman will become separated (bain) with just one divorce, and he cannot take her back, but he can marry her again with a new contract, because a woman with whom intercourse has not taken place becomes separated (bain) with just one divorce, while the one with whom intercourse has taken place becomes separated (bain) with three divorces.

Ibn Shihab used to say: If a man says to a woman, "I am free from you and you are free from me," then three divorces will take place, like an irrevocable divorce.