@techreport{NBERw13155,
 title = "Product Differentiation, Multi-product Firms and Estimating the Impact of Trade Liberalization on Productivity",
 author = "Jan De Loecker",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "13155",
 year = "2007",
 month = "June",
 URL = "http://www.nber.org/papers/w13155",
}