@article{Kovalev:2009uF,
  author = "Kovalev, Yuri Y.  and  Pushkarev, Alexander  and  Lobanov, Andrei  and  Sokolovsky, Kirill",
  title = "{Opacity in parsec-scale jets of active galactic nuclei }",
  doi = "10.22323/1.072.0007",
  journal = "PoS",
  year = 2009,
  volume = "IX EVN Symposium",
  pages = "007"
}