Yahya related to me from Malik from Hisham ibn Urwa from hisfather that Abdullah ibn Masud said, "I do not mind if the iqama forthe subh prayer is called while I am still praying witr." (ES)
App reference (ES): Book 7, Hadith 25 (ES)
USC-MSA web (English) reference: Book 7, Hadith 25 (ES)
Arabic reference (ES): Book 7, Hadith 279 (ES)