The Digital Library of the Astrophysics Data SystemEichhorn, G.Author informationSmithsonian Astrophysical Observatory, 60 Garden Street, MS-83, Cambridge MA 02138, USA, [email protected], http://hea-www.harvard.edu/~gei/geichhorn.htmlAstrophysics and Space Science 247(2):p 189-210, 1997.Copyright ©1997 Kluwer Academic Publishers