Repplinger, Roger. Leg dich, Zigeuner: Die Geschichte von Johann Trollmann und Tull Harder (Munich, Piper, 2008)

Siobhán Dowling writes: "I’m a journalist in Berlin and wrote an article a few years ago about Johann Trollmann, the Sinti boxer who died in a Nazi concentration camp. This is a book about his life: And for your reference, here’s the article I wrote"