@article{KretschmerRungeCoumou2017,
  author    = {Marlene Kretschmer and Jakob Runge and Dim Coumou},
  title     = {Early prediction of extreme stratospheric polar vortex states based on causal precursors},
  journal   = {Geophysical research letters},
  volume    = {44},
  pages     = {8592 -- 8600},
  doi       = {10.1002/2017GL074696},
  year      = {2017},
}