|←Author Index: He||Otto Henker
|Ph.D. Staff member at Zeiss in Jena. Head of the newly established "Medical Optical Instruments" and "Eyeglass" departments from 1912.
This author wrote articles for the 1911 Encyclopædia Britannica.
Articles attributed to this author are designated in EB1911 by the initials "O. Hr."
- “Binocular Instrument” in Encyclopædia Britannica, (11th ed.), 1911.
- “Lens” in Encyclopædia Britannica, (11th ed.), 1911.
- “Microscope” in Encyclopædia Britannica, (11th ed.), 1911.
- http://www.zeiss.de Company History: Otto Henker
|Some or all works by this author are in the public domain in the United States because they were published before January 1, 1923.
The author died in 1926, so works by this author are also in the public domain in countries and areas where the copyright term is the author's life plus 80 years or less. Works by this author may also be in the public domain in countries and areas with longer native copyright terms that apply the rule of the shorter term to foreign works.