Maliks Muwatta Book 2, Hadith Number 44.

Section : Wiping over Leather Socks.

Yahya related to me from Malik from Nafi that Abdullah ibn Umar urinated in the market place and then did wudu, washing his face and hands and wiping his head. Then as soon as he had come into the mosque, he was called to pray over a dead person, so he wiped over his leather socks and prayed.