Around 1997 in Germany (and presumably other Egmont countries). First only in magazines, credits in pocket books followed a little later. Initially the writers were always listed as "co-writers" (as in, co-written with Walt Disney??).
I was getting credits in German magazines at the same time they started giving them in Scandinavian magazines. I believe that was 1990, if I remember correctly. Then, in late 1992 or 1993, The Scandinavian countries stopped giving them, but if I remember correctly, The European courts overruled that, and they were forced to start giving credits again in 1995. I believe that USA started giving them in 1985, with the start of Gladstone's franchise. The Dutch franchise never has given them in ordinary comic books, only in some selected albums.
So how comes that the European court's decision does not apply to the Dutch too?
I was getting credits in German magazines at the same time they started giving them in Scandinavian magazines. I believe that was 1990, if I remember correctly. Then, in late 1992 or 1993, The Scandinavian countries stopped giving them, but if I remember correctly, The European courts overruled that, and they were forced to start giving credits again in 1995. I believe that USA started giving them in 1985, with the start of Gladstone's franchise. The Dutch franchise never has given them in ordinary comic books, only in some selected albums.
So how comes that the European court's decision does not apply to the Dutch too?
Good point. Maybe it was only a Danish court finding, and as Egmont is headquartered in Denmark, it had to follow the court's decision, and it returned the Swedish and Norwegian (and German?) credits to their publications to have uniformity in their operations. I don't really know the details of what went on. Perhaps David G., or someone else on this forum knows the answer to that question.
The French started giving credits in 1983, but only in a few selected albums (like inducks.org/issue.php?c=fr%2FSBD+++1 ) Hachette printed credits in the weekly only in the late 80s, and only for localy-produced comics. Many of these comics were drawn by Comicup studio artists. In that case, credits were given to Comicup only.
Most of the credits for Italian stories were first provided by F. Fossati (at the beginning of the 1980s). Credits for most Dutch stories appeared online in the mid-1990s in the Inducks database first, as far as I know. I'd say credits for most US Disney comic-books were first published by A. Becattini in the Disney Index (1997). The list of Studio stories with credits was first published online in the late 1990s in the Inducks. I'm not sure for the Danish stories. Maybe these were already printed by Martin Olesen in the Carl Barks & Co. fanzine?
Also, the credits in the albums printed by Hachette at the beginning of the 1980s are given for all stories in the book, in no apparent order. In some cases, it was not possible to sort out this information and determine exactly who did what.