Original: Ivan (Janez) Regen (known also as Johann Regen) (December 9, 1868 – July 27, 1947) was a Slovenian biologist, best known for his studies in the field of bioacoustics.
Simplified: Ivan (Janez) Regen (called Johann Regen) (December 9, 1868 – July 27, 1947), was a Slovenian biologist.