Patente
[1] |
H. Kern Zirkel. Patent Nr. CH 29050/508. Eidgenössisches Amt für geistiges Eigtentum (1904). |
[2] |
H. Kern Ruling-Pen. Patent Nr. US 804011. United States Patent Office (1905). |
[3] |
H. Kern Joint for Compasses. Patent Nr. US 808205. United States Patent Office (1905). |
[4] |
H. Kern Compasses. Patent Nr. US 814453. United States Patent Office (1906). |