حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، أَنَّهُ رَأَى أَبَاهُ يَمْسَحُ عَلَى الْخُفَّيْنِ قَالَ وَكَانَ لاَ يَزِيدُ إِذَا مَسَحَ عَلَى الْخُفَّيْنِ عَلَى أَنْ يَمْسَحَ ظُهُورَهُمَا وَلاَ يَمْسَحُ بُطُونَهُمَا ‏.‏

Yahya related to me from Malik from Hisham ibn Urwa that he sawhis father wiping over his leather socks. He said, "When he wiped overhis socks he would never do more than wipe the tops and he would notwipe the bottoms." Translation Not Available

Book Ref: Muwatta Imam Malik Book 2 Hadith 76
Web Ref:  Muwatta Imam Malik Book 2 Hadith 46