Hajek, Professor of Laryngology in Vienna, particularly distinguished himself by his classic work on the acccessory nasal sinuses. Digital facsimile from the Internet Archive at this link. English translation of the fifth edition: Pathology and treatment of the inflammatory diseases of the nasal accessory sinuses ... Translated and edited by Joseph D. Heitger ... and French K. Hansel ... Fifth edition, completely revised and enlarged. 2 vols. St. Louis: Mosby, 1926.