Sahih Bukhari Volume 1, Book 12, Hadith Number 743

Narated By ‘Abdullah bin Abi Qatada : My father said, “The Prophet uses to recite Al-Fatiha followed by another Sura in the first two Rakat of the prayer and used to recite only Al-Fatiha in the last two Rakat of the Zuhr prayer. Sometimes a verse or so was audible and he used to prolong the first Rak’a more than the second and used to do the same in the ‘Asr and Fajr prayers.”