@phdthesis{74454,
  author = {B. Farrell and P.J. Ioannou},
  title = {Optimal state estimation using balanced truncation.},
  year = {2003},
  journal = {Seminar on Predictability of weather and climate, 9-13 September 2002},
  pages = {35-40},
  month = {2003},
  publisher = {ECMWF},
  address = {Shinfield Park, Reading},
  language = {eng},
}