What are "Astérix et ses Amis" and "Uderzo visto por sus Amigos"?

In the wake of the publication of Asterix and the Picts, I did an intensive Google search on whether there are any albums which I had missed out.
Imagine my surprise when I came upon these two comics.
Astérix et ses Amis: I believe it is in French and also translated into about a half a dozen languages, but not English. I think it is a full length comic running to many pages, so I am surprised that it has not been translated to English.
Uderzo visto por sus Amigos is I believe a Spanish book which like the one above has not been translated to English.
However, I have seen images for English cover art, but am not sure whether it is an official publication or fan art - I don't think this has been translated into English.
I wonder if anyone here can give a detailed description of these works, and why they has not yet been translated to English?
I am thinking of sending a mass petition to Asterix publishers to publish these two works in English.

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I'd not heard of these books either, but with just a couple of simple searches it seems fairly clear that neither is a regular story, and neither is part of the official series.
They are volumes by other artists in tribute to Albert Uderzo: the first you mention, more correctly called Astérix et ses Amis - Hommage à  Albert Uderzo [Asterix and Friends - an Hommage to Albert Uderzo], was to mark his 80th birthday in 2007, and the second, which translates as Uderzo as Seen by his Friends, actually came out first, in 2002, so to mark his 75th birthday.
They seem not to be stories, but to be short comic tributes to the author, like a sort of scrap-book.
As for why they have not been brought out in English, well, only the publishers will know for certain, but several thoughts come to mind: they might not be very good; there might be rights issues or legal complications - for example, if artists taking part are represented by different publishers in the English-speaking world; or - and this to me is the most likely - it could just be that no publisher sees a market for the books which would make them cost-effective.
As for a petition, I'm not sure it would have any effect, to be honest - I'm sure if it had been possible to do so, and it was seen to be a way to make money, someone would have done it by now.

"Uderzo visto por sus Amigos" is the Spanish translation for the French book "Uderzo croqué par ses amis" ("Uderzo as Drawn by his Friends") which was first published in 1996. Basically, it is a set of short comic stories written and drawn by various writers and artists.

These stories had Uderzo meeting Asterix in various ways, such as breaching the fourth wall or being an actual character in the story: in one of them he is an artist from Lutetia whom Vitalstatistix commissions to paint a portrait of Asterix; in another he is a Roman Centurion leading an attack on the village. Others give fanciful accounts of how he created the characters, his inspirations etc.

Other Uderzo characters also feature, such as Oumpah-Pah the Redskin or "Tanguy and Laverdure", which is about pilots in the French Air Force.

These stories are not very good. They are very short and basic, some of them lack real plots, others have clumsy storylines due to the lack of available pages. Some of them also include scenes and characters which would mean little to non-French readers. Artist Félix Meynet, for instance, drew a story in which Uderzo meets Meynet's own characters who, as far as I know, have never appeared in English editions, so the point would be lost on readers outside of France.

My own gripe with the book is that Goscinny is hardly mentioned. He makes a couple of cameos and is referred to in passing as "R. G." in one story, but otherwise Uderzo appears to get the full credit for creating "Asterix", which I find very unfair.