En route air traffic control

Chicago citation style
United States. Air Traffic Service. En route air traffic control. 1967-. Retrieved from the Digital Public Library of America, http://catalog.hathitrust.org/Record/003350283. (Accessed November 20, 2018.)
APA citation style
United States. Air Traffic Service, (1967-) En route air traffic control. Retrieved from the Digital Public Library of America, http://catalog.hathitrust.org/Record/003350283
MLA citation style
United States. Air Traffic Service. Retrieved from the Digital Public Library of America <http://catalog.hathitrust.org/Record/003350283>.
Note: These citations are programmatically generated and may be incomplete.