Wickert, J., Arras, C., Beyerle, G., Dick, G., Heise, S., Helm, A., Ramatschi, M., Schmidt, T., Stosius, R., Rothacher, M. (2008): GPS Atmosphere Sounding at GFZ: Overview and comparison of CHAMP data with MOZAIC, International PGGM-IAGOS Workshop (Taipeh 2008) (Taipeh).