The link to the official English page is for the G13 gakus or "Best of Compilations" which contain handpicked chapters from the series, with the last volume containing what was a then recent chapter about the 2000 US presidential election. The gakus didn't do very well, hence all the volumes, including volume 1 only received one printing. I'm thankful, if nothing else, that Viz has them available digitally for Amazon Kindle.
What's rather amusing about the whole thing is that Takao Saito's other works were released, albeit digitally, on erenta, and Amazon Kindle. Works like "Hawking", "Dingo", "Barom-1", "MUYONOSUKE", and of course "Doll: The Hotel Detective" from Saito Pro and LEED themselves (I'll create mangadex pages for them with links to purchase). But G13 remains elusive.
I suppose its length is fundamentally what deters LEED from doing a full on publication, despite the international setting and plotlines. Hopefully the interest sparked by "The Professional" and the 2008 anime (both have videos on YT amassing over 150K views each) will encourage them to take another chance at releasing the manga (perhaps another set of gakus?) but that's just wishful thinking on my end, so I suppose I shouldn't get too carried away.
Just something I thought everyone should know.