You will have to set up a free account at the Internet Archive if you want to read more than a few pages.
AT numbers assigned to stories can come from the author of the collection or from Ashlimann's
A Guide to Folktales in the English Language.
Anything not assigned an AT number has NA, for "not available" or "not assigned."
Folktales of Norway / Reidar Christiansen
This link above goes to a copy of this book in the Internet Archive.
The links below go to individual stories in this book.
You will have to set up a free account if you want to read more than a few pages.