Muwatta Malik:Tahajjud:Hadith 279
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَبْدَ اللَّهِ بْنَ عَبَّاسٍ، وَعُبَادَةَ بْنَ الصَّامِتِ، وَالْقَاسِمَ بْنَ مُحَمَّدٍ، وَعَبْدَ اللَّهِ بْنَ عَامِرِ بْنِ رَبِيعَةَ، قَدْ أَوْتَرُوا بَعْدَ الْفَجْرِ ‏.‏

Yahya related to me from Malik that he had heard that Abdullah ibn Abbas and Ubada ibn as-Samit and al-Qasim ibn Muhammad and Abdullah ibn Amir ibn Rabia had all prayed witr after the break of dawn.