Sahih Bukhari, Chapter: Prayers (Salat)

Musa bin 'Uqba said, "I saw Salim bin 'Abdullah looking for some places on the way and prayed there. He narrated that his father used to pray there, and had seen the Prophet praying at those very places." Narrated Nafi' on the authority of Ibn 'Umar who said, "I used to pray at those places." Musa the narrator added, "I asked Salim on which he said, 'I agree with Nafi' concerning those places, except the mosque situated at the place called Sharaf Ar-Rawha."