What sites have links to the largest variety of product concordances?
Haveman’s Empirical Investigations in International Trade (http://www.eiit.org/Trade. Resources/TradeCordances.html) has country codes (Census Bureau, World Bank, Penn World Tables), classification lists, and crosswalk product classification tables (HS, NAICS, SIC, ISIC, End use). For SIC, NAICS, SITC, and End-use concordances, see (http://www.tradeinfo.net) for a cd-rom (fee).