1. Bell, G. D. and Halpert, M. S. (1995) Interseasonal and interannual variability: 1986 to 1993, NOAA Atlas No. 12, Dept. of Commerce.
2. Chao, B. F. (1985) Excitation of the Earths Chandler wobble by Southern Oscillation–El Niño, 1900–1979, NASA–GSFC TM-86231.
3. Not available