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 * [Optimal Bidding in Online Auctions (2001)](http://www.mit.edu/~dbertsim/papers/Revenue%20Management/Optimal%20Bidding%20in%20Online%20Auctions.pdf) by Dimitris Bertsimas, Jerey Hawkinsy, Georgia Perakis 
 
+* [Online Ad Auctions (2009)](online-ad-auctions.pdf) by Hal Varian
+
 ## Open Source
 
 * [The Simple economics of Open Source  (2000)](http://www.people.hbs.edu/jlerner/simple.pdf) by Josh Lerner and Jean Tirole
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