A&A Supplement Ser., Vol. 124, September 1997, 509-515
Received October 22, accepted December 10, 1996
M.N. Sevenster1, J.M. Chapman2,3, H.J. Habing1, N.E.B. Killeen3, and M. Lindqvist4
Send offprint request: M.N. Sevenster
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