@article{Cao Long:2004,
  author  = "V. Cao Long and P. Goldstein and S. Vu Ngoc",
  title   = "On existence of solitions for the second harmonic equations of a laser beam",
  journal = "Acta Physica Polonica A",
  volume  = "Vol. 106",
  number  = "no 6",
  pages   = "843--852",
  year    = "2004",
}