@article{Gavrilova:2019Bn,
  author = "Gavrilova, Margarita  and  Teryaev, Oleg",
  title = "{Frame-independent angular distributions as density matrix in-variants}",
  doi = "10.22323/1.352.0287",
  journal = "PoS",
  year = 2019,
  volume = "DIS2019",
  pages = "287"
}