He was the author of Kaferbuch (on beetles) Conchylienbuch (on shells) and  Schmetterlingsbuch  (on butterflies and moths) and Die Fortpflanzung europäischer und aussereuropäischer Vögel.
He was the author of Beetle Compendium (on beetles), Shelled Creatures Compendium (on shells), and Butterfly and Moth Compendium  (on butterflies and moths) and European and Non-European Bird Reproduction.