21. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 10 January 1956 Genre: Letters (correspondence)
22. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 4 January 1956 Genre: Letters (correspondence)
23. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 15 December 1955 Genre: Letters (correspondence)
24. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 17 November 1955 Genre: Letters (correspondence)
25. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 21 October 1955 Genre: Letters (correspondence)
26. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 2 May 1955 Genre: Letters (correspondence)
27. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 22 March 1955 Genre: Letters (correspondence)
28. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 4 February 1955 Genre: Letters (correspondence)
29. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 28 January 1955 Genre: Letters (correspondence)
30. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 10 November 1954 Genre: Letters (correspondence)