BIG BROTHER & THE HOLDING CO. Avalon Ballroom San Francisco Concert (1967 US promotional-only 5" x 7 & 1/2" postcard for the August 24-27, 1967 concerts at the Avalon Ballroom, San Francisco, which featured Big Brother & The Holding Company, Bo Diddley, Bukka White, Salvation Army Banned & North American Ibis Alchemical Co.)