@manual{75715,
  author = {Franco Molteni},
  title = {Empirical orthogonal function analysis in the zonal and eddy components of 500 mb height fields in the Northern extratropics},
  year = {1987},
  number = {61},
  pages = {36},
  month = {01/1987},
  publisher = {ECMWF},
  address = {Shinfield Park, Reading},
  language = {eng},
}