وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، وَابْنِ، شِهَابٍ وَسُلَيْمَانَ بْنِ يَسَارٍ أَنَّهُمْ كَانُوا يَقُولُونَ عِدَّةُ الْمُخْتَلِعَةِ ثَلاَثَةُ قُرُوءٍ ‏.‏

Yahya related to me from Malik that he had heard that Said ibnal-Musayyab and Ibn Shihab and Sulayman ibn Yasar all said, "The iddaof the woman with a khul divorce is three periods." Translation Not Available

Book Ref: Muwatta Imam Malik Book 29 Hadith 1221
Web Ref:  Muwatta Imam Malik Book 29 Hadith 60