Landolt-Börnstein. Numerical data and functional relationships in science and technology. New Series. Group_VI: Astronomy, astrophysics and space research. Volume_2: Astronomy and astrophysics. Extension and supplement to Volume_1. Subvolume_c: Interstellar matter - Galaxy - Universe.K. H. Hellwege, Gert Zech, H. H. Voigt et al.|Unknown|1982Cited by 0