| The Condensed Chemical Dictionary, 9th Edition, Revised by Hawley, Van Nostrand Reinhold Co., (1977), pp. 630, 636. |
| H. Van Olphen: "An Introduction to Clay Colloid Chemistry," 2nd Ed., John Wiley & Sons, New York, London, Sydney, Toronto (1963), p. 64. |
| "Industrial Minerals and Rocks," 4th Ed., S. J. Lefond, Ed., American Institute of Mining, Metallurgical and Petroleum Engineers, Inc., New York, N.Y. (1975), pp. 1244-1247. |
| R. E. Grim: "Clay Mineralogy," 2nd Ed., McGraw Hill Book Co., New York, St. Louis, San Francisco, Toronto, London, Sydney (1968), pp. 77-79. |