Geostatistical interpolation of abiotic site conditions in the Netherlands : a method for reference mapping / A.M.F. Bio ... [et al.]Spatial interpolation of sea bird densities on the Dutch part of the North Sea / Edzer J. Pebesma, Richard N.M. Duin, Ana M.F. BioLandsdekkende interpolatie van aanwezigheid van plantensoorten / Edzer J. Pebesma, Ana M.F. Bio