Yahya related to me from Malik from Rabia ibn Abi Abd ar-Rahman
that al-Qasim ibn Muhammad and Urwa ibn az-Zubayr said that a man who
had four wives and then divorced one of them irrevocably, could marry
straightaway if he wished, and he did not have to wait for the
completion of her idda.
Muwatta Malik Book 28, Hadith 58