1. Letter from Maxine Singer to Francis Crick Creator: Singer, Maxine Date: 31 October 1962 Genre: Letters (correspondence)
2. Letter from Francis Crick to Maxine Singer Creator: Crick, Francis, 1916-2004 Date: 6 November 1962 Genre: Letters (correspondence)
3. Letter from Maxine Singer to Severo Ochoa Creator: Singer, Maxine Date: 22 October 1959 Genre: Letters (correspondence)