1Justin Eins.From Salinas to Burlington.Cananarmy of paywalls big and small buoy Gannett? 尼曼实验室网站.http.//www.niemanlab.org/2012/O2/from-salinas-to-burlington-~can-an- army-of-paywaUs-big-and-small-bouy-gannett/?readnext.
2Jon Radoff.A Brief History of Paywalls,http.//radoff.com/ blog/2009/11/30/a-brief-history-of-paywalls/.
3The media'srisky paywall experiment. A timeline,The Week, July 30, 2010, http.//theweek.com/article/index/205465/the-mecfias- riskv-!oaywall- ex!oeriment - a- fimeline.
4Richard Perez-Pena.Times to Stop Charging for Parts of Its Web Site,The New York Times, September 18, 2007, http.//www.ny- fimes.com/2007 /oq/18/business/media/18fimes-html?_r=3&hp.
5Five Failed Paywalls and What We Can Learn from Them,Business Insider, October 25,2011,http.//www.businessin- sider.com/failed-paywalls-2010-4.
6Natlves.Success of paywalls at smaller papers is good sign for pr int,5/3/2010,Vol.81Issue18,p8-119.
