Danmarks gamle Folkeviser is a collection of (in principle) all known texts and recordings of the old Danish popular ballads.
It drew both on early modern manuscripts, such as Karen Brahes Folio, and much more recent folk-song collecting activity.
During the nineteenth century, Axel Olrik was also heavily involved, editing volumes 6-8.
Grundtvig's classifications were: It is now standard practice to refer to the Danish ballad type by its assigned a DgF number.
Also it is commonplace to refer to ballad titles by Grundtvig's normalized orthography rather than actual spellings occurring in the texts.