Richard P. Feynman to Judah Cahn, March 15, 1983 / Heidi Houston to Richard P. Feynman, May 2, 1983 / Richard P. Feynman to Heidi Houston, May 13, 1983 (interoffice memorandum) / Richard P. Feynman to Paul Privateer, November 9, 1983 by Richard P. Feynman narrated by Richard Poe / Heidi Houston & Michelle Feynman narrated by Johanna Parker