1. Gähler, R., Kalus, J. & Mampe, W. J. Phys. E13, 546 (1980).
2. Klein, A. G. & Opat, G. I. in Neutron Interferometry (eds Bonse, U. & Rauch, H.) (Oxford University Press, 1980).
3. Soret, J. L. Poggendorff's Annalen (1875).
4. Andrews, Optics of the Electromagnetic Spectrum, 276 (Prentice-Hall,New Jersey, 1960).
5. Wood, R. W. Phil. Mag. 45, 511 (1898).