It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "The night prayer is two by two (rak'ahs); then when you fear the onset of dawn, pray one rak'ah to make it witr."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith except Yahya bin Sulayman."