APA

United States, . (1990). User guide and index airworthiness directives small aircraft and rotorcraft. [Washington, D.C: .

Chicago

United States, . 1990. User guide and index airworthiness directives small aircraft and rotorcraft. [Washington, D.C: .

Harvard

United States, . (1990). User guide and index airworthiness directives small aircraft and rotorcraft. [Washington, D.C: .

MLA

United States, . User guide and index airworthiness directives small aircraft and rotorcraft. [Washington, D.C: . 1990.