TY  - BOOK
ED  -  Institution of Electrical Engineers, London
TI  -  Thermionic valves, 1904 -1954 : :  the fifty years
U1  -  Q 621.384132 INS 
PY  - 1955///
CY  -  London : 
PB  -  [s.n], 
KW  -  Vacuum-tubes
N1  -  Includes the Lectures given at the institution's special meeting, No v. 16,1954, and a catalogue of the exhibition, held Nov.15 -17, 1954
ER  -