article by Edward M. Sion et al published March 1990 in The Astrophysical Journal Supplement Series

scientific article published in Astronomical Journal

scholarly article

scholarly article in Bulletin of the American Astronomical Society, vol. 23, 1991

scientific article published in the Astrophysical Journal

scientific article published in January 1986

scientific article published in the Astrophysical Journal

scientific article published in the Astrophysical Journal

scientific article published in January 1993