1. Alliance for Excellent Education. The high cost of high school dropouts---What the nation pays for inadequate high schools. Issue Brief Washington D.C. 2007. Alliance for Excellent Education. The high cost of high school dropouts---What the nation pays for inadequate high schools. Issue Brief Washington D.C. 2007.
2. Cameron L. and Bazelon C. The impact of digitization on business models in copyright-driven industries: A review of the economic issues. The Brattle Group Inc. 2013; http://brattle.com/_documents/UploadLibrary/Upload951.pdf. Cameron L. and Bazelon C. The impact of digitization on business models in copyright-driven industries: A review of the economic issues. The Brattle Group Inc. 2013; http://brattle.com/_documents/UploadLibrary/Upload951.pdf.
3. Are the costs of 'free' too high in online education?