To cite package 'spcosa' in publications use:

Dennis Walvoort [aut, cre, cph], Dick Brus [aut, cph], Jaap de Gruijter [aut, cph] (2-03). Spatial Coverage Sampling and Random Sampling from Compact Geographical Strata. R package version 0.3-0. http://CRAN.R-project.org/package=spcosa

de Gruijter, J., Brus, D., Bierkens, M. and Knotters, M. (2006) Sampling for Natural Resource Monitoring. Springer, Berlin, ISBN 978-3-540-22486-0

Brus, D. J., Spatjens, L. E. E. M., and de Gruijter, J. J. (1999) A sampling scheme for estimating the mean extractable phosphorus concentration of fields for environmental regulation Geoderma 89: 129-148

Walvoort, D. J. J., Brus, D. J., and de Gruijter, J. J. (2010) An R package for spatial coverage sampling and random sampling from compact geographical strata by k-means Computers & Geosciences 36: 1261-1267 Available online at http://dx.doi.org/10.1016/j.cageo.2010.04.005

See de Gruijter et. al. (2006) and Walvoort et al. (2010) for an introduction to spatial coverage sampling and its applications. Refer to Walvoort et al. (2-03) for the spcosa package. See Brus et. al. (1999) for stratified simple random sampling for composites.

Corresponding BibTeX entries:

  @Manual{,
    title = {Spatial Coverage Sampling and Random Sampling from Compact
      Geographical Strata},
    author = {Dennis Walvoort and Dick Brus and Jaap de Gruijter},
    year = {2-03},
    note = {R package version 0.3-0},
    url = {http://CRAN.R-project.org/package=spcosa},
  }

  @Book{,
    title = {Sampling for Natural Resource Monitoring},
    author = {J. de Gruijter and D. Brus and M. Bierkens and M.
      Knotters},
    publisher = {Springer},
    address = {Berlin},
    year = {2006},
    note = {ISBN 978-3-540-22486-0},
  }

  @Article{,
    title = {A sampling scheme for estimating the mean extractable
      phosphorus concentration of fields for environmental regulation},
    author = {D. J. Brus and L. E. E. M. Spatjens and J. J. de
      Gruijter},
    journal = {Geoderma},
    year = {1999},
    volume = {89},
    pages = {129--148},
  }

  @Article{,
    title = {An R package for spatial coverage sampling and random
      sampling from compact geographical strata by $k$-means},
    author = {D. J. J. Walvoort and D. J. Brus and J. J. de Gruijter},
    journal = {Computers & Geosciences},
    year = {2010},
    volume = {36},
    pages = {1261--1267},
    note = {Available online at
      http://dx.doi.org/10.1016/j.cageo.2010.04.005},
  }