1 "Fișier:Patent_for_a_System_for_signaling_US1367583.pdf".

Fișier:Patent for a System for signaling US1367583.pdf

STATES PATENT OFFICE. BORNETT L. BOBROFF, OF MILWAUKEE, WISCONSIN. SYSTEM FOR SIGNALING. 1,367,583.Specification of Letters Patent. Patented Feb. 8,...