1. Letter from Leon A. Heppel to Maxine Singer Creator: Heppel, Leon A.National Institutes of Health (U.S.) Date: 13 December 1955 Genre: Letters (correspondence)
2. Letter from Leon A. Heppel to Maxine Singer Creator: Heppel, Leon A. Date: [2 June 1968?] Genre: Letters (correspondence)
3. The Polymerization of Guanosine Diphosphate by Polynucleotide Phosphorylase Creator: Singer, MaxineHeppel, Leon A.Hilmoe, Russell Date: March 1960 Publisher: American Society for Biochemistry and Molecular Biology Genre: Articles
4. The Mechanism of Action of Polynucleotide Phosphorylase Creator: Singer, MaxineHeppel, Leon A.Hilmoe, Russell Date: [1959] Publisher: New York Academy of Sciences Genre: Articles
5. Letter from Leon A. Heppel to Maxine Singer Creator: Heppel, Leon A.National Institutes of Health (U.S.) Date: [28 December 1957?] Genre: Letters (correspondence)
6. Letter from Leon A. Heppel to Maxine Singer Creator: Heppel, Leon A.National Institutes of Health (U.S.) Date: [27 July 1958?] Genre: Letters (correspondence)
7. Letter from Leon A. Heppel to Maxine Singer Creator: Cornell UniversityHeppel, Leon A. Date: 5 December 1985 Genre: Letters (correspondence)
8. Letter from Leon A. Heppel to Maxine Singer Creator: Heppel, Leon A. Date: [13 December 1974] Genre: Letters (correspondence)
9. Letter from Leon A. Heppel to Maxine Singer Creator: Heppel, Leon A.National Institutes of Health (U.S.) Date: 27 October 1955 Genre: Letters (correspondence)
10. Letter from Leon A. Heppel to Maxine Singer Creator: Cornell UniversityHeppel, Leon A. Date: [5 June 1971] Genre: Letters (correspondence)