- Statistical methods with R -> SemivariogramExp.R (lines 1-80)
  - Experimental semivariogram -> Semivariogram-exp.R
  - model of semivariogram -> Variogram-Teo.R
  - Kriging -> Kriging2017 (inverse distance method, simple block kriging, ordinary kriging)
        - crossvalidation

  * in exam we can use the maximum of selected points