Musnad Abu Ya'la al-Mawsili 148:44

Abu Sa’id al-Ashajj narrated to us, he said: ‘Uqbah bin Khalid narrated to me, he said: Yusuf bin Ibrahim al-Tamimi narrated to me, that he heard Anas bin Malik saying: The Messenger of Allah (peace and blessings of Allah be upon him) was asked: "Which of your household is most beloved to you?" He said: "Al-Hasan and al-Husayn." He said: So he used to say to Fatimah: "Call my two sons for me," then he would smell them and press them to himself.