1. Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment October 1999
2. Hansen , A. T. Walter J. Blanch P. Enge Ionospheric Spatial and Temporal Correlation Analysis for WAAS September 2000
3. Walter , T. A. Hansen J. Blanch P. Enge Robust Detection of Ionospheric Irregularities September 2000
4. Coster , A. J. J. C. Foster P. J. Erickson F. J. Rich Regional Mapping of Storm Enhanced Density During the July 15-16, 2000 Geomagnetic Storm June 6, 2001