The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 2047
Umm 'Atiyya reported: There came to us the Messenger of Allah (may peace be upon him) as we were washing one of his daughters. So he said: Wash her (dead body) an odd number of times, five times or more than that, the rest of the hadith is the same. She (further) said: We braided her hair in three plaits: (two) on the sides of her head and one on her forehead.