1. Letter from Severo Ochoa to Maxine Singer Publication: Produced: 11 November 1957 Subject(s): PolynucleotidesPolyribonucleotide Nucleotidyltransferase Archival Collection: The Maxine Singer Papers (Profiles in Science)
2. Letter from Severo Ochoa to Maxine Singer Publication: Produced: 24 May 1958 Subject(s): PolynucleotidesPolyribonucleotide Nucleotidyltransferase Archival Collection: The Maxine Singer Papers (Profiles in Science)