article published September 1994 in European Physical Journal C

scholarly article published September 1996

article published September 1995 in European Physical Journal C

scientific article published in 1998

scholarly article

article by J. Breitweg et al published May 2001 in Physics Letters B

scientific article published in 1995

scientific article published in 1995

scientific article published in 1993

scientific article published in 1998

scientific article published in Physical Review Letters

scientific article published in 1995