Nothing against her at all, but you probably don't want to be taking writing advice from Roberta Williams. She basically plagiarized from her sources. Jane Jensen was probably working from a bunch of hefty tomes on mythology (Bulfinch's, Ovid's), which I don't think is really what you're looking for.
If you're seriously interested in writing, read a lot and don't limit yourself to only the niche you are interested in. Still, there's almost endless fantasy literature to read at this point. In terms of classic fantasy I'd recommend Fritz Leiber and Michael Moorcock. More recently, Neil Gaiman and China Mieville do kind of fairy-taleish fantasy, though it's probably a bit different than what you're thinking of. David Eddings wrote fairly 'light' high fantasy, though people have fairly mixed opinions on the quality. I'd also highly recommend the Codex Alera by Jim Butcher (high fantasy based on Roman mythology, basically)
If you're interested in puzzle solving and riddles, you might check out The Gold Bug by Edgar Allen Poe. There's tons of collections of riddles and such that you can find all over the place though.
These are my principles. If you don't like them, I have others.