00446nam a2200169Ia 4500003000900000008004100009040001600050080001900066100001800085245006100103260003200164300001000196650001900206650002100225650001100246700001900257IN-BaIIA211028s9999    xx            000 0 eng d  cIIA Library  a621.385.1bHAL  aHallows, R. W 0aIntroduction to valvescR. W. Hallows and H. K. Milward.  aLondonbIliffe & Sonsc1953  a152p.  aNASA thesaurus  aNumotic circuits  aValves  aMilward, H. K.