To cite package 'spcosa' in publications use:

D.J.J. Walvoort, D.J. Brus, and J.J. de Gruijter (2009). Spatial Coverage Sampling and Random Sampling from Compact Geographical Strata. R package version 0.2-0. 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) Geoderma 89: 129-148

Refer to Walvoort et al. (2009) for the spcosa package. See de Gruijter et. al. (2006) for spatial coverage sampling. 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 = {D.J.J. Walvoort and D.J. Brus and and J.J. de Gruijter},
    year = {2009},
    note = {R package version 0.2-0},
    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},
  }