Egan, Walter G. Optical properties of inhomogeneous materials : applications to geology, astronomy, chemistry, and engineering / Walter G. Egan and Theodore W. Hilgeman. - New York : Academic Press, 1979. - xi, 235 pages : illustrations ; 24 cm. Includes index Bibliography: p. 221-226 ISBN: 0122326504 Subjects--Topical Terms: Inhomogeneous materials--Optical properties.