@article{Choi:2009jE,
  author = "Choi, Ho-Meoyng  and  Ji, Chueng-Ryong",
  title = "{Perturbative QCD analysis of exclusive $e^+ e^-  \to  J/\Psi + \eta_c$}",
  doi = "10.22323/1.061.0016",
  journal = "PoS",
  year = 2009,
  volume = "LC2008",
  pages = "016"
}