Musnad Abu Ya'la al-Mawsili 150:206

'Abd al-A'la narrated to us, Yazid ibn Zuray' narrated to us, Sa'id narrated to us, from Qatadah, who said: We wrote to Ibrahim ibn Yazid asking him about breastfeeding. He wrote back: "Shurayh narrated that 'Ali and Ibn Mas'ud used to say: 'A little or a lot of breastfeeding makes [marriage] prohibited.'" He said: "And it was in his letter that Abu al-Sha'tha' al-Muharibi narrated that 'Aishah narrated that the Prophet of Allah, may Allah bless him and grant him peace, used to say: 'One or two gulps do not make [marriage] prohibited.'"