@unpublished{LiLiSoffetal.2005,
  author  = {Qingfeng Li and Zhuxia Li and Sven Soff and Marcus Bleicher and Horst St{\"o}cker},
  title   = {Probing the density dependence of the symmetry potential at low and high densities},
  institution = {Physik},
  year    = {2005},
}