An interesting sample essay about Zorki 35M forerunners, which cameras influenced its construction and concept and also the echoes together other makers.
Indoubtably the forerunner of rangefinder renaissance.
Included, the rangefinder technics
Note: the correcct reding sequence must be:
Zorki 35M origins 1a
Zorki 35M origins 21a
Zorki 35M rangefinder parts description