Yahya related to me from Malik from Hisham ibn Urwa from hisfather that A'isha, umm al-muminin said, "The Messenger of Allah, mayAllah bless him and grant him peace, used to pray thirteen rakas inthe night and then would pray two rakas when he heard the adhan forthe subh prayer."
App reference: Book 7, Hadith 10
USC-MSA web (English) reference: Book 7, Hadith 10
Arabic reference: Book 7, Hadith 264