That theory isn't widely accepted (like you'd see if you looked it up on wikipedia). mises.org is a libertarian organization advocating the austrian school of economics, which is often quite divorced from reality.
You're not going to take my word it, but feel free to see for yourself. Watch their lectures on YouTube ("misesmedia"), and you'll get it.
Velocity of money? Concomitant effects, huh? .. I suspect you might be some sort of government shill though. Very few actual Libertarians don't see Austrian economics for the rational truth it is.