Col Reference --- --------- R1 Christian C.A. 1981, Astrophys. J. 246, 827 R2 Becker W., et al. 1976, Univ. Basel. Katalogue ... Back to the form
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R1 Christian C.A. 1981, Astrophys. J. 246, 827
R2 Becker W., et al. 1976, Univ. Basel. Katalogue ...