Richard P. Feynman to H. H. Barschall, November 30, 1965 / Richard P. Feynman to the Brothers of Pi Lambda Phi, November 2, 1965 / Walter Bleakney to Richard P. Feynman, October 22, 1965 (telegram) / Richard P. Feynman to Walter Bleakney, October 29, 1965 / Lars Söderström to Richard P. Feynman, October 27, 1965 / Richard P. Feynman to Lars Söderström, November 19, 1965 by Richard P. Feynman narrated by Richard Poe / Walker Bleakney & Lars Söderström narrated by Johanna Parker