The paper can be found also at the site http://arxiv.org in the category CS.SC with the number 0604052.
Readme : (1.5 Kb) File explains what is inside external.tar.gz.
InstallFermat : (0.8 Kb) How to obtain and install the program Fermat.
external.tar.gz : (618 Kb) All examples of the paper in extform.ps and an experimental version of FORM to run them.
extform.ps : (372 Kb) The postscript file of the article about the external channels.
extform.ps.gz : (171 Kb) The gzipped version of the postscript file of the article about the external channels.
extform.pdf : (235 Kb) The pdf file of the article about the external channels.
extform.pdf.gz : (209 Kb) The gzipped version of the pdf file of the article about the external channels.