S. Gernsback's Radio Encyclopedia (1931) plus RCA "Definitions and Symbols" (1930)
New York: S.Gernsback, C. 1931. Second Edition. Quarto, 12 x 9.25 inches, stiff maroon flexible imitation leather card covers, very good, light rubbing and wear to edges of covers, contents very good, a bit toned. 352 pp, illustrated. Loosely inserted is RCA Institutes' "Definitions and Symbols" (C. 1930), a glossary.....