@article{Baumgaertel2009,
  author    = {Hellmut Baumgaertel},
  title     = {Spectral and scattering theory of Friedrichs Models on the positive half line with Hilbert-Schmidt perturbations},
  doi       = {10.1007/s00023-009-0398-8},
  url       = {http://www.springerlink.com/content/105443},
  year      = {2009},
}