@inbook{74314,
  author = {ECMWF},
  title = {IFS Documentation CY28R1 - Part II: Data Assimilation - Chapter 9 only},
  abstract = {<p>
  Chapter 9 ‘Observation processing'</p>
},
  year = {2004},
  journal = {IFS Documentation CY28R1},
  number = {2},
  month = {2004},
  publisher = {ECMWF},
  url = {https://www.ecmwf.int/node/9196},
  doi = {10.21957/iz80xsg8w},
  note = {<p>
  Operational implementation 9 March 2004</p>
},
  language = {eng},
}