(Inggris) David Sadava; H. Craig Heller; David M. Hillis (2009). Life: The Science of Biology. Macmillan. hlm. 767–. ISBN978-1-4292-1962-4. Diakses tanggal 12 October 2010.Parameter |coauthors= yang tidak diketahui mengabaikan (|author= yang disarankan) (bantuan)
CHNOPS: The Six Most Abundant Elements of Life, Pearson BioCoach, 2010, accessed 2010-12-09. "Most biological molecules are made from covalent combinations of six important elements, whose chemical symbols are CHNOPS. ... Although more than 25 types of elements can be found in biomolecules, six elements are most common. These are called the CHNOPS elements; the letters stand for the chemical abbreviations of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur."
wsj.com
online.wsj.com
New Link in Chain of Life, Wall Street Journal, 2010-12-03, accessed 2010-12-05. "Until now, however, they were all thought to share the same biochemistry, based on the Big Six, to build proteins, fats and DNA."