@misc{80474,
  keywords = {Symposium, 4D-Var},
  author = {J. Derber},
  title = {The early years of variational data assimilation: A perspective from NCEP},
  year = {2018},
  journal = {Symposium: 20 years of 4D-Var at ECMWF},
  month = {2018},
  language = {eng},
}