@phdthesis{73445,
  author = {Erik Andersson and Carla Cardinali and L. Isaksen and Anotonio Garcia-Mendez},
  title = {On the impact of frequent data in ECMWF's 4D-Var scheme. Hourly surface pressure data, European profilers and profiling aircraft data},
  year = {2001},
  journal = {Eighth Workshop on Meteorological Operational Systems, 12-16 November 2001},
  pages = {179-183},
  month = {2001},
  publisher = {ECMWF},
  address = {Shinfield Park, Reading},
  language = {eng},
}