@misc{indiciaea6dbcfa772e3,
  title = {On-line estimation of nonlinear physical systems},
  author = {G. Christakos},
  year = {1988},
  doi = {10.1007/bf00918881},
  url = {https://pubs.usgs.gov/publication/70013645},
  note = {Source identifier: 70013645}
}