General Motors Corporation. In matter of Delco Radio Division of General Motors Corporation and International Brotherhood of Electrical Workers, affiliated with A. F. of L.: [same] and United Automobile Workers of America, affiliated with A. F. of L.; [same] and Metal Polishers, Buffers, Platers & Helpers Int'l Union, Local No. 24, affiliated with A. F. of L., cases nos. R-1948 to R-1850: supplemental decision and certification of representatives, Nov. 20, 1940.