Mark Minguillon to Richard P. Feynman, April 14, 1976 / Richard P. Feynman to Mark Minguillon, April 23, 1976 / Mark Minguillon to Richard P. Feynman, July 31, 1976 by Mark Minguillon & Michelle Feynman narrated by Johanna Parker / Richard P. Feynman narrated by Richard Poe