Source: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1364 [Terms] [Paper]
See also: PAC, 1992, 64, 143. (Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)) on page 165 [Terms] [Paper] White Book, 2nd ed., p. 110 [Terms] [Book]