Estimating Soil Moisture Using Optical and Radar Satellite Remote Sensing Data, Natali, Stefano, Pellegrini Loreto, Rossi Gianluigi, Giordano Ludovica, Iannetta Massimo, Schino Gabriele, Marini Alberto, and Nabil Gasmi , Desertification and Risk Analysis Using High and Medium Resolution Satellite Data, p.105-116, (2009)