(1) Robert Hill and Joseph Needham, The Chemistry of Life: Eight Lectures on the History of Biochemistry (London, England: Cambridge University Press, 1970), page 17 ; (2) Richard B. Silverman, The Organic Chemistry of Enzyme-catalyzed Reactions, 2nd ed.
Erhard Friedrich Leuchs (1831) "Wirkung des Speichels auf Stärke" (Effect of saliva on starch), Poggendorff's Annalen der Physik und Chemie, vol. 22, page 623 (modern citation: Annalen der Physik, vol. 98, no. 8, page 623).