This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Terje Spurkland's academic survey works philologically from the Norwegian runic corpus specifically, reading the inscriptions themselves and dating and interpreting them against known runic alphabets and documented Old Norse language change across the whole period runes were used in Norway.
That focused, single corpus study matters for a Younger Futhark rune entry because it grounds a rune's documented form and use in one clearly bounded, checkable body of actual carved texts rather than in a generalized account drawn loosely from Scandinavia as a whole, and an entry can cite it specifically where a claim concerns Norwegian inscriptional practice.
A Younger Futhark rune entry therefore records, where Spurkland's study documents it, how a rune's form or use is attested in the Norwegian corpus across the period, noting honestly that a claim about Anglo-Saxon runes or about later esoteric reinterpretation needs a different source, since this study stays inside the linguistic and historical evidence of Norway's own inscriptions. Spurkland's own survey also documents how the corpus itself spans several documented centuries of use, from the earliest transitional inscriptions through the fully developed sixteen character row, and an entry can note where a rune's attested form changed across that documented span.