This is a guide to the material contained in
http://www.math.gatech.edu/~thomas/OLDFTP/four/,
an exact copy of the files formerly located on a now defunct
anonymous ftp server.
It falls naturally into two parts, Reducibility and Discharging.
Common to both parts is the file
unavoidable.conf, a list of the 633 unavoidable configurations
stored in the following format:
 N; a character string identifying the configuration;
 n r a b; where
 n is the number of vertices of the free completion;
 r is the ringsize;
 a is the cardinality of C ; and
 b is the cardinality of C' (see discussion
before (3.2) in the paper);
 k [2*k integers]; k is the number of edges in X, each edge being
represented as a pair of integers;
 the adjacency list of the free completion in a standard form
(the second column contains
the degrees in the free completion);
 coordinates of vertices of the free completion;
the ith entry in the coordinate list is 1024 x + y where [x,y] are the coordinates
of vertex i, (0 < = x,y < 1024) .
Vertices 1,...,r are the ring vertices (in order),
and so the configuration itself consists of vertices r + 1,
r + 2, ... n .
The set is also available in a
pictorial version.
Reducibility:
All of the above are now available at
arXiv:1401.6481.
Discharging:

unavoidable.conf, described above.

discharge.c, the program that verifies that the files
present7,
present8,
present9,
present10, and
present11
describe correct unavoidability proofs.

discharge.tex, documentation for the above program.

rules, the list of the discharging rules in a machine readable form.
They are also available in
humanreadable form.

discharge.pas, a Pascal version of the discharging program, written
by
Christopher Carl Heckman.
All of the above are now available at
arXiv:1401.6485.