What is a single word meaning "authoritative source of knowledge"?

I'm looking for a word that means authoritative source of knowledge.

The word would preferably be a noun and could refer to a group of people or a collection of knowledge. Additionally it'd be strongly preferred if the word would not be a derivative of encyclopedia.

Solution 1:

You could simply call it an authority, and that could stand for a human guru or a tome.

Solution 2:

My choice would be cornbread ninja's, but s/he beat me to it. Authority:

5. an accepted source of information, advice, etc.
7. an expert on a subject: He is an authority on baseball.

I like the word pundit, not least because it's a coveted Stack Exchange badge. Other words for learned and authoritative people could be guru, savant, or sage.

There's also cognoscenti:

plural noun, singular -te
persons who have superior knowledge and understanding of a particular field, especially in the fine arts, literature, and world of fashion.

Solution 3:

The canon is the collective term for those authorities which are indisputable (originally a religious term, but now general). So a book may be canonical. I don't think either should be applied to people, though, to avoid confusion.