APA

United States, . (1980). Air taxi operators and commercial operators. [Washington, D.C: .

Chicago

United States, . 1980. Air taxi operators and commercial operators. [Washington, D.C: .

Harvard

United States, . (1980). Air taxi operators and commercial operators. [Washington, D.C: .

MLA

United States, . Air taxi operators and commercial operators. [Washington, D.C: . 1980.