In depth websites about Frigg (Norse Mythology)?

I am doing a paper for my art history cl trying to connect the mythologies and images between Frigg and the Virgin Mary but can't seem to find enough reliable sources on the web. I've found tons of "fan" sites and when I did a .edu search the pages I found were very brief. Anyone out there know of a HELPFUL webpage that has to do with Frigg, including cited pictures I can use for comparison? .Org's and .Edu's only, please... citing a .Com is too unreliable and looks horrible in a bibliography!