Sahih Bukhari Volume 002, Book 020, Hadith Number 201.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 20. Shortening The Prayers (At-Taqseer)
Narated By 'Abdullah bin Dinar : On traveling, 'Abdullah bin 'Umar used to offer the prayer on his Mount by signs whatever direction it took. 'Abdullah said that the Prophet used to do so.