Muwatta Malik 1254
موطأ مالك#1254SahihMalik said, "This is what is done among us." Malik added, "If she does not have a menstrual period, her idda is three months
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMaqtu Sahih
In-book reference: 29:51