@manual{76409,
  author = {Adrian Simmons and J. Chen},
  title = {The calculation of geopotential and the pressure gradient in the ECMWF atmospheric model: Influence on the simulation of the polar atmosphere and on temperature analyses.},
  year = {1990},
  number = {66},
  pages = {79},
  month = {07/1990},
  publisher = {ECMWF},
  address = {Shinfield Park, Reading},
  language = {eng},
}