Hadith 10:182
Abu Bakr narrated to us, he said: Hushaym narrated to us, from Yunus and Abu Hurrah, regarding Al-Hasan, concerning a man who said to his wife, "You are divorced, so observe the waiting period (iddah)." He said: It is one [divorce]. And if he said, "You are divorced, so observe the waiting period; you are divorced, so observe the waiting period," then it is two [divorces].
حدثنا أبو بكر قال نا هشيم عن يونس وأبي حرة عن الحسن في رجل قال لأمرأته أنت طالق فاعتدي قال هي واحدة وإذا قال أنت طالق فاعتدي أنت طالق فاعتدي فهي اثنتان