Holmyard 1957, p. 170; cf. Friedlander 1992, pp. 75–76. For the symbols, see Holmyard 1957, p. 149 and Bergman's table as shown above. Holmyard, Eric J. (1957). Alchemy. Harmondsworth: Penguin Books. OCLC2080637. Friedlander, Walter J. (1992). The Golden Wand of Medicine: A History of the Caduceus Symbol in Medicine. Contributions in Medical Studies, 35. New York: Greenwood Press. ISBN0-313-28023-1. Holmyard, Eric J. (1957). Alchemy. Harmondsworth: Penguin Books. OCLC2080637.