Prayer (Kitab Al-Salat): Detailed Rules of Law about the Prayer during Journey
Dawud :: Book 4 : Hadith 1285
Narrated Umm Hani ibn AbuTalib:
The Apostle of Allah (peace_be_upon_him) prayed on the day of the Conquest (of Mecca) eight rak'ahs saluting after every two rak'ahs.