Ioannis Scylitzae Synopsis Historiarum. Editio Princeps. Rec. Ioannes Thurn, p. 341-342, in: Corpus Fontium Historiae Byzantinae 5 Series Berolinensis, 1973
Tsamakda V.: The illustrated chronicle of Ioannes Skylitzes in Madrid, p. 221
[Johannes Skylitzes / Madrid Skylitzes -- Public domain -- http://commons.wikimedia.org/wiki/File:Skylitzes-Ouranos kills Bulgarians.jpg]