The Book of Purification (Kitab Al-Taharah)
Muslim :: Book 2 : Hadith 539
Shuraib b. Hani reported: I asked 'A'isha about wiping over the shoes. She said: You better go to 'Ali, for he knows more about this than I. I, therefore, came to 'Ali and he narrated from the Apostle (may peace be upon him) like this.