1. Alfvén, H., Cosmical Electrodynamics. Oxford, Clarendon Press, 1950.
2. Birkeland, Kr., Norwegian Aurora Polaris Expedition, 1902–03. Christiania, Vol. 1, Part 1, 1908; Part 2, 1913.
3. Chapman, S., and Bartels, J., Geomagnetism, Vol. II. Oxford, Clarendon Press, 1940. (See pp. 850–890)
4. Fritz, H., Das Polarlicht. Leipzig, Brockhaus, 1881.
5. Harang, L., The Aurorae. London, Chapman (in press).