Dobyns, Jay and Johnson-Shelton, Nils and Rometsch, Martin. Falscher Engel: Mein Höllentrip als Undercover-Agent bei den Hells Angels. Ullstein Taschenbuch, Year 2011.

Raiswell, Richard. Lavezzo, Kathy, Angels on the Edge of the World: Geography, Literature and English Community, 1000-1534, Ithaca 2006. In The Medieval Review , Year 2007.