Keywords: Patenturkunde Karl Spitzenberg Russland 1906.jpg en patent certificate Karl Spitzenberg Russia 1906 2012-05-04 own Bmontag Patenturkunde Karl Spitzenberg Russland 1906 Cropped jpg PD-RusEmpire Insignia cc-by-sa-3 0 1906 patents Karl Spitzenberg 1906 documents 1906 in art |