Tolkien was a Christian, he was inspired by Norse and Anglo-Saxon literature, mythology and archeology. Best to go to the sources rather than rely on 20th century a story teller or neopagan authors.
I would advise going directly to the source, most of which are freely available online:
Norse Sources:
The Poetic and Prose Eddas,
The Norse Sagas,
Saxo Grammaticus, history of the Danes, AKA
Gesta Danorum,
Futhark
In addition for an academic interpretation:
Neil Price:The Viking Way
Neil Price: The Children of Ash and Elm.
Also
Norse Mythology for Smart People - The Ultimate Online Guide to Norse Mythology and Religion
Anglo-Saxon Sources:
Bede, 673 – 735: Ecclesiastical History of the English People,.
Anglo Saxon Chronicles,
Nennius, 770 – 810, Historia Brittonum,
Anglo-Saxon Charms
Futhorc
In addition for an academic interpretation:
Bill Griffiths; Aspects of Anglo-Saxon Magic.
J. Arnold; The Archeology of Early Anglo-Saxon Kingdoms.
Also
Aspects of Anglo-Saxon Paganism – Tha Engliscan Gesithas