@article{Niinuma:2015by,
  author = "Niinuma, Kotaro  and  Kino, Motoki  and  Doi, Akihiro",
  title = "{Multi-epoch and multi-frequency VLBI observation of X-ray to gamma-ray flare in TeV blazar Mrk 421}",
  doi = "10.22323/1.230.0101",
  journal = "PoS",
  year = 2015,
  volume = "EVN 2014",
  pages = "101"
}