Cultural industries are those industries considered critical to maintaining the cultural heritage of a region or country. Most often the term refer to the exclusion of certain industries from FREE TRADE agreements. (Citizens and politicians in many countries fear U.S. cultural dominance.) In addition to challenging existing cultural norms, cultural industries are a significant source of revenue. Many governments, including the United States, subsidize cultural industries in order to maintain them. The U.S.-Canada Free Trade Agreement (1989) and NORTH AMERICAN FREE TRADE AGREEMENT (NAFTA) (1994) both contain provisions protecting primarily Canadian cultural industries. The acts restrict trade and control of publishing, distributing, or selling books, periodicals, newspapers, films, videos, audio or video music recordings, and printed or machine-readable music. The acts also define public-radio communications and all radio, television, and cable TV broadcasting as cultural industries; and allow unilateral retaliation against actions affecting cultural industries. NAFTA also protects certain cultural products such as Mexican tequila and Kentucky bourbon. Under the agreement, only producers in each country can use these terms to describe their products.