2. Letter from Sol Spiegelman to Tracy M. Sonneborn Creator: Spiegelman, Sol, 1914-1983 Date: 22 September 1947 Genre: Letters (correspondence)
3. Letter from Sol Spiegelman to Jacques Monod Creator: Spiegelman, Sol, 1914-1983 Date: 25 October 1946 Genre: Letters (correspondence)
4. Letter from Sol Spiegelman to Harlyn O. Halvorson Creator: Spiegelman, Sol, 1914-1983 Date: 14 October 1954 Genre: Letters (correspondence)