Musnad Ahmad 1250:1

Sufyan ibn 'Uyaynah narrated to us, from Ayyub, from Muhammad, from Umm 'Atiyyah: The Messenger of Allah (peace and blessings of Allah be upon him) came out to us while we were washing his daughter. He said: "Wash her three times, or five times, or more than that if you see fit. And put camphor, or something of camphor, in the final washing. When you have finished, inform me." So we informed him, and he threw his waist-wrapper (izar) to us and said: "Shroud her in it." Muhammad said: And Hafsah narrated it to us, saying: "So we braided her hair into three braids."