1. Patent Information on the Internet;Spear;World Patent Information,1996
2. WIPO Standard ST.32,1996
3. International Standard ISO 8879:1986,1986
4. Clark, J., SGMLS. The source code is available for anonymous ftp from ftp.jclark.com in the directory /pub/sgmls. (An SGML parser based on the ARCSGML parser materials which were written by Charles F. Goldfarb.)