Soil moisture and surface roughness measurements during HAPEX-Sahel 1992 : ground data collection report / P.J. van Oevelen, D.H. Hoekman en M.A.M. VissersNOPEX/FOREST-DYNAMO : ground data collection and data analysis report : fieldcampaigns in 1994-1995 / P.J. van Oevelen and I.H. WoodhouseRESMEDES Spain 1996 : ground data collection and analysis report / P.J. van Oevelen, M.A.M. Vissers and I.H. WoodhouseEstimation of areal soil water content through microwave remote sensing / Peter J. van Oevelen