Friedrich Engels
Steven D. Levitt
United States. General Accounting Office
England and Wales. Sovereign (1625-1649 : Charles I).
Canada. Parliament. House of Commons.
Canada
United States. Congress. Senate. Committee on Education and Labor.
United States. Congress. Senate. Committee on Agriculture and Forestry
Loren C. Eiseley
United States. Bureau of the Census
Great Britain. Certification Office for Trade Unions and Employers' Associations.
United States. Congress. Senate. Committee on the Judiciary
R. R. Bowker
Charles R. Miller
Patricia Millard
United States. Congress. Senate. Committee on Interstate Commerce
European Economic Community.
Gale Group
United States. Federal Trade Commission.
Robert A. Brady