books.google.de - Tariffs and their impact on trade have played a major role in American history since colonial times. The primary issue leading to the separation of the colonies from Great Britain, the tariff has remained one of the most divisive issues in American history. It is also a frequently misunderstood issue....http://books.google.de/books/about/Encyclopedia_of_Tariffs_and_Trade_in_U_S.html?hl=de&id=aPrlkDP3OzwC&utm_source=gb-gplus-shareEncyclopedia of Tariffs and Trade in U.S. History: The encyclopedia
