Hi! I was curious about the topic, so here's some research I've made:

According to Maddox games official site (the site died long time ago, so you can use its copies on Wayback machine), in Russia Z.A.R. was published by Auric Vision, and outside of the country the publishers were Tetratel and Explorer Software.
One more thing about Z.A.R. - this game was actually developed to fully support early VR gear (3d helmets, 3d glasses and so on), and this Tetratel company was actually a dealer of these old VR sets (EyeFX controllers in particular). You can actually find a scan of Z.A.R. game cover with Tetratel and EyeFX logos, and that's the picture of the boxed copy of the game coming only with and for the EyeFX VR gear. This version (Tetratel edition) of the game was also featured on their site for free so EyeFX users can download it.
As for Explorer Software, there is little information about the company, but it is clear that it collapsed before year 2000. It is unclear how they were involved in Z.A.R release.

So, probably the only actual boxed PC version of the game is the Russian CD version released in 1997. I have one of them, and information from the box had helped a lot in this little research. :) The disk contains Russian only version of the game, CD soundtrack and some promotional materials (demos of Madspace and GAG and various screenshots of the Maddox games products).

Sources:
https://web.archive.org/web/20000118181353/http://maddox.aha.ru/ZAR/zar.htm
https://web.archive.org/web/20000311193729/http://www.tetratel.com/download/download.htm
http://www.stereo3d.com/eyefx.htm

do you have a picture of the disk?

Yes, here's some
https://postimg.org/gallery/3arrleoni/
I'm not selling it btw, because the game from this very disk was the first game I've played on my own computer years ago :)

See this. but all information here in Russian ((( http://www.old-games.ru/game/568.html