@article{GregoryCotterReich2016,
  author    = {A. Gregory and C. J. Cotter and Sebastian Reich},
  title     = {MULTILEVEL ENSEMBLE TRANSFORM PARTICLE FILTERING},
  journal   = {SIAM journal on scientific computing},
  volume    = {38},
  pages     = {A1317 -- A1338},
  doi       = {10.1137/15M1038232},
  year      = {2016},
}