Source: http://arichlife.passionsaving.com/2012/05/11/i-definitely-need-to-cite-some-of-your-work-as-the-founder-of-valuation-informed-indexing-as-i-have-not-found-anyone-else-who-can-lay-claim-to-that-shiller-pointed-out-the-predictive-power-of-pe1/