Letter from Aflred D. Hershey to Sydney Brenner #1, 6/10/1953
Letter from Aflred D. Hershey to Sydney Brenner #2, 3/9/1957
Letter from Alfred D. Hershey to Seymour Benzer, 19/11/1957
Letter from Sydney Brenner to Alfred D. Hershey #1, 1/10/1953
Letter from Sydney Brenner to Alfred D. Hershey #2, 18/10/1953
Mapping under the the switch hypothesis, by Alfred D. Hershey, 18/11/1957