Messages to Students and Teachers:
GPS Science Report: Elevation Number Changes
GPS Science Report: GPS Receiver Numbers
Global Positioning System Report by Whit Smith, Ph.D.

Science Reports:
Use, Quality, and Availability of GPS Data Recorded in the GLOBE Pre-College Science-Education Program Arlie, VA 1997

Web Chats:
Archive of November 19, 1999 GIS Web Chat
Archive of May 20, 1998 GPS Web Chat