1. A. Koestler, Insight and Outlook, Macmillan, London and New York, 1949.
2. E. Lendvai, in Module, Proportion, Symmetry, Rhythm, G. Kepes, ed., George Braziller, New York, 1966.
3. N. Angier, “Why Birds and Bees, Too, Like Good Looks.” The New York Times, February 8, 1994, p. C1. The title of the article can be taken as referring to one of Cole Porter’s most popular songs “Let’s Do It” (“Let’s Fall in Love”) that starts with the words, “that’s why birds do it, bees do it,…”
4. V. Prelog, “Chirality in Chemistry.” Science 1976, 193, 17–24.
5. Quoted in C. A. Coulson, “Symmetry.” Chem. Britain 1968, 4, 113–420.