Abu Dawud Book 2, Hadith Number 1342.

Chapter : On the number of rakahs of the prayer at night.

Narated By N/A : The above mentioned tradition has also been transmitted by Bahz b. Hakim through a different chain of narrators. This version adds: He (the Prophet) would offer the night prayer and go to his bed. In this version, there is no mention of praying four rak’ahs. The narrator then transmitted the rest of the tradition. This version further says: He would pray eight rak’ahs during which his recitation of the Qur’an, bowing and prostration were all equal. He would sit only after the eighth rak’ah, and then stand up without uttering the salutation, and pray one rak’ah observing witr prayer and then give the salutation raising his voice so much so that we were about to awake. The narrator then transmitted the tradition to the same effect.