Mullard Magic: For All Your Vintage Valve and Radio Needs!
AEI, TRANSISTOR BETA TESTER, TYPE B2285, LEAFLET, 1962
MULLARD, 3X DOCUMENTS, CIRCUITS FOR AUDIO SERVICING EQUIPMENT, NEWSLETTER NO 24, 1958, NEWSLETTER NO 35, 1962
SERVICE VALVE EQUIVALENTS, RSGB, BOOK, 5TH EDITION, 1962