The Wikipedia article is quite well-documented. For the "You know who my friends are. You will have to ask them if they are Communists." quote, the citation is Testimony of Burl Icle Ives, New York, N.Y. [on May 20, 1952]," Hearings before the Subcommittee to Investigate the Administration of the Internal Security Act and Other Internal Security Laws of the Committee on the Judiciary, United States Senate, Eighty-Second Congress, Second Session on Subversive Infiltration of Radio, Television, and the Entertainment Industry. Washington, D.C.: GPO, 1952. Part 2, pp. 205–228