For more information on bootstrap see Weisstein, Eric W. "Bootstrap Methods." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/BootstrapMethods.html
On many systems, web browsers can download, unzip, and untar these files automatically. On UNIX systems, after downloading the file bootstrap.tgz, the individual files within the zipped tar file can be unbundled by executing the commands tar -zxf bootstrap.tgz.
Alternatively, please follow links to pages from where individual files of the distributions can be downloaded.