CGER METEX -- an online application developed by the Jiye Zeng for air trajectory calculation.
Re2C -- the lexer generator used by ZeScript engine.
OpenGL -- the rendering engine of ZeGraph.
cairo -- used by ZeGraph for 2D plot.
SFL -- The Standard Function Library used by ZeScript.
CEPHES -- math library used by ZeScript's matrix library for statistics and special functions.
NetCDF -- an interface for array-oriented data access used by ZeGraph.
HDF -- a library for scientific data management used by ZeGraph.
GSHHS -- the place to download global coastline data.
ETOPO -- NOAA' web site for global relief data. Here is another site for ETOPO data (resulted from google search of "netCDF etopo60").
Mesa -- an OpenGL clone.