Hah. I'll bite.
http://www.imperial-library.info/content/pocket-guide-empire-and-its-environs-first-edition is written by Michael Kirkbride and Kurt Kuhlmann. It is extremely informative, straightfoward in its language, and forms the basis for probably about half of all we know about Tamriel. It is only "ambiguous" in the sense that it is written from a clear in-universe point of view with motives other than simply informing (in other words, it's propaganda, which also happens to be true in many cases).
The http://www.imperial-library.info/content/imperial-census-daedra-lords is simple and interesting, but should not be taken in isolation. Like the above, it's Imperial in origin.
The http://www.imperial-library.info/content/seven-fights-aldudagga are just really fun, and while just as metaphorically complex as anything else he's written they are also good stories in themself. It reflects on Nordic history and literature and makes a good substitute for the lack of any weighty (read: "MKish") metaphysical texts in TES V. The only thing you might take issue with is the language is unusually vernacular in parts, and more [loreword of great importance]-y in others - partly for reasons of humour, and partly because it's old Breto-Nordic story, written for commoners and not necessarily scholars.
http://www.imperial-library.info/content/lord-vivecs-sword-meeting-cyrus-restless is a good fun tale, although the fact that it's about Cyrus fighting Vivec might be strange enough in itself to relegate it to "dubious authenticity".
Oh, and there's http://www.imperial-library.info/content/cosmology which is there precisely for the purpose of clarifying stuff like the 36 Lessons and Monomyth.
By the way: none of the above are in-game (although the PGE came with the game). If you want in-game ones, it'll take a bit of digging, because MK's style is really the only way of identifying stuff he contributed to in the game - devs don't put their names on stuff unless it's posted online, really. Loads of "simple" stuff from Morrowind is probably by him, but I can't say it is with certainty.