1. Chapman, S., Bartels, J., Geomagnetism, London: Oxford University Press, 1940, 639–668.
2. Langel, R. A., The main field, in Geomagnetism (ed. Jacobs, J. A.), Vol. 1, London: Academic Press, 1987, 249–512.
3. Zmuda, A. J., The International Geomagnetic Reference Field, 1965.0, in World Magnetic Survey (ed. IUGG), IAGA Bulletin, 1971, 28: 1–10.
4. IAGA Commission 2, Working Group 4, International Geomagnetic Reference Field 1965.0, J. Geophys. Res., 1969, 74(18): 4407–4408.
5. IAGA Division 1, Study Group on Geomagnetic Reference Field, International magnetic reference field 1975, J. Geomag. Geoelectr., 1975, 27(12): 437–439.