1. Newton I. The Mathematical Principles of Natural Philosophy. Motte A, translator. Daniel Adde, New York, NY. 1846. p. 83. Available at https://archive.org/details/newtonspmathema00newtrich. Accessed 15 April 2016.
2. Pasteur L. On the extension of the germ theory to the etiology of certain common diseases. Ernst HC, translator. Available at https://ebooks.adelaide.edu.au/p/pasteur/louis/exgerm/complete.html. University of Adelaide, Adelaide, Australia. Accessed 15 April 2016.
3. The germ theory, beriberi, and the deficiency theory of disease
4. Aristotle. Physics, Book II, part 3. Available at http://classics.mit.edu/Aristotle/physics.2.ii.html. Accessed 15 April 2016.
5. US Department of Health and Human Services. Healthy People 2020 framework. Available at https://www.healthypeople.gov/sites/default/files/HP2020Framework.pdf. Accessed 15 April 2016.