Musannaf Ibn Abi Shayba 27:409

'Affan narrated to us, he said: Hammad bin Zayd narrated to us, from Yahya bin Sa'id, from Salim, he said: 'Abdullah bin 'Umar said: "You have criticized 'Uthman for things that, if 'Umar had done them, you would not have criticized them."