Electric time switches
作者： Horstmann Bevan Graham
DOI:
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lens.org 参考文章(4)
William K Newman, Robert J Aust, Variable timer switch ,(1953)
Daniel V Tuttie, Combination controller and timer ,(1954)
Ellis John Wyndham, Clock-controlled switch gear ,(1947)
Lauren W Guth, Time switch apparatus ,(1956)