http://www.opengl.org/resources/libraries/glut/ provides the
distribution for the GLUT library (The OpenGL Utility
Toolkit) originally written by Mark Kilgard. Version 3.5 or later is
required.
http://www.libpng.org/pub/png/
is the website for the PNG library.
Version 0.96 or later is required. The zlib library
may also be obtained at this location.
http://www.libgd.org/
is the current site for the gd library (a C API
for GIF creation), originally written by Thomas Boutell. Version 1.3
or later should be used. This version does not use
LZW compression, so it avoids the legal problems with the Unisys
patent on that algorithm.
Version 1.2 of gd can be also be used with MolScript without
modification, but since this version of gd uses LZW compression, it is
not recommended for legal reasons.
The Protein Data Bank
(PDB) at RSCB. This is the scientific data bank where
published protein 3D coordinate data sets are deposited by the
scientists and from where the data sets can be retrieved by
anyone. The specification of the PDB coordinate file format is
available. The 3D data sets can be searched in different ways.