Tariff Schedules of the United States Annotated

Effective 1979 to January 1989, the U.S. import statistics were initially
collected and compiled in terms of the commodity classifications in the
Tariff Schedules of the United States Annotated (TSUSA), an official
publication of the U.S. International Trade Commission embracing the legal
text of the Tariff Schedules of the United States (TSUS) together with
statistical annotations. This publication was superseded by the Harmonized
Tariff Schedule of the United States Annotated for Statistical Reporting
Purposes (HTSUSA) in January 1989.

Effective 1979 to January 1989, the U.S. export statistics were initially
collected and compiled in terms of the commodity classifications in
Schedule B, Statistical Classification of Domestic and Foreign Commodities
Exported from the United States. Schedule B is a U.S. Bureau of the Census
publication and, during this period, was based on the framework of the
TSUS. In January 1989, this publication was replaced by Schedule B based
on the Harmonized System.