Musnad Ahmad 1153:608

Muhammad ibn Idris—meaning al-Shafi‘i—narrated to us, he said: ‘Abd al-‘Aziz ibn Muhammad narrated to us, from Yazid ibn al-Had, from Muhammad ibn Ibrahim, from Abu Salamah, that he said: I asked ‘Aishah, the wife of the Prophet, may Allah bless him and grant him peace: "In how many [garments] was the Messenger of Allah, may Allah bless him and grant him peace, shrouded?" She said: "In three white Sahuli garments."