Hi,
on this site, it seems we can buy Ars Magica books.
But:
It seems a cheap way of having the books... i'm interested!
Well, in fact, they don't have
Arts&academies, Faerie, Magic, Hedge magic... 
Edit: is this one
a 5th edition book?
I can only answer to your last question : the book you look after is a pdf book for Ars Magica 5th Edition.
Atlas generally waits until the initial print run is sold out before converting the book to PDF for sale on E23.
You can transfer the files between hard drives. I keep copies on my laptop for when I travel. I've never tried to print, but it is my understanding that you can print them.
Ah...
Mmmh. Well, i hope they will have the books i want in the only shop i know which sell roleplaying games ... don't want to pay a maximum for transport
I'd imagine that any good bookshop will be able to order Ars Magica books in for you. You just need the ISBN number. And if it really is a good bookshop, they shouldn't charge you for ordering.
Good or not doesnt matter.
Many bookstores will have to use nonstandard suppliers to get some "rare" books(among which RPGs are often included unless the store commonly has gaming books anyway) and while they can get it cheaper than you can order it yourself, sometimes it still costs much more than a normal purchase for the store.
I'll search the list of atlas ars magica 5th edition and their ISBN then 
Here's one to get you started. Tales of Mythic Europe: 1-58978-110-4
Tales of Mythic Europe: 1-58978-110-4
The Lion and the Lily ISBN: 1-58978-100-7
Art & Academe ISBN:1-58978-101-5
Realms of Power: Magic 1-58978-102-3
Realms of Power: Faerie 1-58978-105-8
Hedge Magic, Revised Edition 1-58978-104-X
from the site.
Huh,
I'm confused now:
I've found on another site this:
Hedge Magic, Revised Edition 978-1-58978-104-X
Why the ISBN has a 978- before the isbn on the atlas website?
If i go to a shop (what i'm going to do tonight) shall i use the first (with 978) or second (without) to ask for a command?
The ISBN switched from 10-digit format to 13-digit format a couple of years ago: en.wikipedia.org/wiki/Internatio ... ook_Number (although that article is a little confusing). So older books have had their 10-digit ISBNs "converted" to 13-digit ones. I would use the 978 prefix when shopping for the book - but if they don't like it, just throw it away. You know, like the Certamen rules. 
Okay, thanks!