Editore: Institution of Electrical Engineers,, [London]:, 1939
Da: Zephyr Used & Rare Books, Vancouver, WA, U.S.A.
Prima edizione
4to. 19, [1] pp. Numerous diagrams, charts, graphs. W/o wrappers as issued, minor dustoilng, chwng to uppr bk crnr, G. First edition of this proof copy of paper to be presented before the IEE.