Prayer (Kitab Al-Salat): Detailed Rules of Law about the Prayer during Journey
Dawud :: Book 4 : Hadith 1275
Narrated Aisha, Ummul Mu'minin:
Dhakwan, the client of Aisha, reported on the authority of Aisha: The Apostle of Allah (peace_be_upon_him) used to pray after the afternoon prayer but prohibited others from it; and he would fast continuously but forbid others to do so.