Google is your friend. (I looked for the authoritative documentation you'd demand, but came a point I've got other things to do than preemptively do research for the skeptical. Suffice to say it's widely referenced, if a bit hard to pin down.)
ETA: I'd prefer research to snide retorts. I researched it to my satisfaction, you research it to yours; comparing the results would be much more enlightening than a put-down.
ETA: I'd prefer research to snide retorts. I researched it to my satisfaction, you research it to yours; comparing the results would be much more enlightening than a put-down.