Hans Haubold, UN Outer Space Office, Vienna International Centre, Vienna, Austria A. M. Mathai, Department of Mathematics and Statistics, McGill University, Montréal, Québec, Canada
This article is published in the Encyclopedia of Applied Physics,
Vol. 23 (Page 47 - 81), 1998 WILEY-VCH Verlag GmbH, ISBN: 3-527-29476-7