@techreport{LS-84,
  author = {P. L{\"o}nnberg and D.B. Shaw},
  title = {ECMWF Data Assimilation - scientific documentation, 3rd ed.},
  year = {1992},
  journal = {Meteorological Bulletin: Research Manual 1},
  number = {M1.5/1},
  month = {1992},
  publisher = {ECMWF},
  address = {Shinfield Park, Reading},
  note = {<p>
  Original version published in 1984</p>
},
  language = {eng},
}