1 2 Partington, J.R. (1989). A Short History of Chemistry. Dover Publications, Inc. ISBN0-486-65977-1.
↑ Frankland, E. (1852). Phil. Trans., vol. cxlii, 417.
↑ Petikan asal dalam bahasa Inggeris: "A tendency or law prevails (here), and that, no matter what the characters of the uniting atoms may be, the combining power of the attracting element, if I may be allowed the term, is always satisfied by the same number of these atoms."
