Abu Dawud
Prayer
Book Number: 002 / Hadith Number: 1242
Chapter : A seventh view that imam should lead each section in one rakah severellay and they should not pray the second rakah by themselves.
Narated By Ibn 'Abbas : Allah, the Exalted, prescribed prayer for you, through the tongue of the Prophet (pbuh), four rak'ahs while resident, two rak'ahs while travelling and one rak'ah in the time of danger.