I failed to find what the "vol. 97, 2004" part of the question's citation refers to, or a formal journal or proceedings publication for that paper. It is much earlier (made public in November 2000).
The first author cites his paper (at line 38 in the conference paper section here) as:
BARRETO, P. S. L. M.; Rijmen, V.; 2000: The KHAZAD Legacy-Level Block Cipher. In: 1st Open NESSIE Workshop, 2000, Leuven (Belgium). Proceedings of the 1st Open NESSIE Workshop.
The second author cites his paper (at line 235 here) as:
P. S. Barreto, and V. Rijmen, "The Khazad legacy-level block cipher," In Proceedings of the 1st NESSIE Workshop, 15 pages, 2000.
It also has been cited as
P. Barreto and V. Rijmen. The Khazad Legacy-Level Block Cipher. In
First Open NESSIE Workshop, KU-Leuven, 2000. Submission to NESSIE.
If I had to cite this paper on this website, it could be as:
Paulo S.L.M. Barreto and Vincent Rijmen, The KHAZAD Legacy-Level Block Cipher, submission to First Open NESSIE Workshop, 13-14 November 2000, Leuven, Belgium; file khazad/B/Khazad.pdf in khazad.zip.
The closest I found to 2004 is that Paulo Barreto cites (in the Other publications section here) a different, shorter paper,
V. Rijmen, BARRETO, P. S. L. M., “The Khazad Block Cipher,”, The Perl Journal 7, p. 5, 2003.
It is online here and was apparently an insert in this.
Addition: if there was ever formal Proceedings of the 1st Open NESSIE Workshop, its current web presence is this. Here are the remains of a Nessie Book planned circa 2004.