1. Aris, R., Vectors, Tensors and the Basic Equations of Fluid Mechanics, Prentice Hall, Englewood Cliffs, N.J., 1962.
2. Booker, H. G., Proc. Roy. Soc. A, 155 (1936) 235.
3. Booker, H. G., Phil. Trans. A, 237 (1939) 411.
4. Booker, H. G., J. Geophys. Res. 54 (1949) 243.
5. Budden, K. G., Radio Waves in the Ionosphere, Cambridge University Press, Cambridge, 1961.