1. The biological problem of to-day: preformation or epigenesis? : The basis of a theory of organic development Author(s): Hertwig, Oscar, 1849-1922, author Publication: New York : The Macmillan Co., [1900] Subject(s): HeredityGeneticsDevelopmental BiologyWeismann, August, 1834-1914.
2. Our Approach to Developmental Biology Publication: Produced: 2 March 1972 Subject(s): Developmental Biology Archival Collection: The Francis Crick Papers (Profiles in Science)
3. Letter from Francis Crick to Leo Sachs, Weizmann Institute of Science Publication: Produced: 17 September 1970 Subject(s): Developmental Biology Archival Collection: The Francis Crick Papers (Profiles in Science)