21. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 4 January 1956 Genre: Letters (correspondence)
22. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 10 January 1956 Genre: Letters (correspondence)
23. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 24 September 1958 Genre: Letters (correspondence)
24. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 11 August 1960 Genre: Letters (correspondence)
25. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R.United States. Public Health Service. Federal Security Agency Date: 24 September 1951 Genre: Letters (correspondence)
26. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R.United States. Public Health Service. Federal Security Agency Date: 14 March 1951 Genre: Letters (correspondence)
27. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R. Date: 14 December 1949 Genre: Letters (correspondence)
28. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R.United States. Public Health Service. Federal Security Agency Date: 8 November 1951 Genre: Letters (correspondence)
29. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R.United States. Public Health Service. Federal Security Agency Date: 14 November 1951 Genre: Letters (correspondence)
30. Letter from P. R. Edwards to Joshua Lederberg Creator: Edwards, Philip R.United States. Public Health Service. Federal Security Agency Date: 4 October 1951 Genre: Letters (correspondence)