Yahya related to me from Malik from Nafi that Salim ibn 'Abdullahsaid, "I was with Abdullah ibn Umar on a journey and after the sun hadrisen I saw him do wudu and then pray. So I said to him, 'This isn't aprayer that you normally do. 'He said, 'After I had done wudu for thesubh prayer, I touched my genitals. Then I forgot to do wudu. So I didwudu again and repeated my prayer.' "
USC-MSA web (English) reference: Book 2, Hadith 65
Arabic reference: Book 2, Hadith 95