William F. Friedman NSA Archive - Extracted Correspondence Related to Patent Information Related to Theodore I. Przysiecki and Dehn (US Patent Nos. 2,405,570 and 2,401,507), 1947-1948 - 4in1

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Files W.F.F. Archive Patent and Equipment Records Extracted Correspondence Related to Patent Information Related to Theodore I. Przysiecki and Dehn (US Patent Nos. 2,405,570 and 2,401,507), 1947-1948

Proposed Application for Patent of Theodore X. Prayslecki for Orientation Device (Case #4), 1 April 1948

Document A71103

U.S. Patent Nos. 2,405,570 and 2,401,507, 24 September 1947

Document A71102