1. Bendat, J. S., and A. G. Piersol, 1971: Random Data: Analysis and Measurement Procedures. Wiley, 407 pp.
2. Born, M., and E. Wolf, 1975: Principles of Optics, 5th Ed. Pergamon Press, 808 pp.
3. Böttger, H, and K. Fraedrich, 1980: Disturbances in the wavenumber-frequency domain observed along 50°N. Contribution to Atmos. Phys., 53, 90°106.
4. Childers, D. G., 1978: Modern Spectrum Analysis. IEEE Press (reprint series), New York, 334 pp.
5. Deland, R. J., 1964: Traveling planetary waves. Tellus, 16, 271-273.