Muwatta Malik
The 'Aqiqa
Hadith #6
26.6
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّهُ عُقَّ عَنْ حَسَنٍ، وَحُسَيْنٍ، ابْنَىْ عَلِيِّ بْنِ أَبِي طَالِبٍ .
Yahya related to me from Malik that he heard that there had been an aqiqa for Hasan and Husayn, the sons of Ali ibn Abi Talib