APA

United States, . (19). Importance of transponder operation & altitude reporting. [Washington, D.C: .

Chicago

United States, . 19. Importance of transponder operation & altitude reporting. [Washington, D.C: .

Harvard

United States, . (19). Importance of transponder operation & altitude reporting. [Washington, D.C: .

MLA

United States, . Importance of transponder operation & altitude reporting. [Washington, D.C: . 19.