Christopher Paul Carey found this cover on the internet. It is of the Italian Urania Fantasy magazine, with a translation of Farmer's novel Hadon of Ancient Opar (Opar, la città immortale) There is no additional information about this publication given on the webpage.

On the cover you can see that it was 'published' by Mondadori in February 1976.

There is only one place on the internet where you can see this cover. On one of the pages of the website Photobucket.com.
Chris didn't find this publication in the PJF Bibliography, and asked me if I knew anything about the magazine.

I did not know about this one, and had never seen the picture before.
My research did not give any information about this issue. It looks like that it never was printed or published. Mondadori actually published the novel, but then in a paperback in 1989, in their 'Oscar Fantasy' series. In that book are no references of an earlier publication.

I also searched in the online Italian listings of all of the several Urania series. Mondadori had a Urania Fantasy series, but that one only started in 1988. None of the shown issues look anywhere near the above shown cover.

My conclusion: this is a phantom or ghost edition. I added it on the page 'Ghost Editions'.