scientific article published in December 2002

scientific article published in September 1994

scientific article published in 1995

scholarly article by Edwin Henneken et al published January 2007 in Learned Publishing

scientific article published in January 1989

scientific article published on 25 September 2009

scientific article published in January 2002

scientific article published in January 2002

scientific article published in December 2002

scientific article published in November 1999

scientific article published in Astronomy and Astrophysics

scientific article published in April 2000

scientific article published in Astronomy and Astrophysics

scientific article published in Astronomy and Astrophysics

scientific article published in January 2002

scientific article published in 2004

scientific article (publication date: December 2005)