1. Anon.: “Report of the definitions panel on definitions to be used in the description and analysis of drag”. ARC CP No. 369, 1957.
2. G. Gabrielli: “On the subdivision in different “forms” of the aircraft drag at the maximum speed”. Troisième Congrès Aéronautique Européen, 1958, pp. 398–407 and 979–984.
3. H. Schlichting and E. Truckenbrodt: “Aerodynamik des Flugzeuges”, Band 1 und 2, Springer Verlag, Berlin, 1962.
4. D.E. Hoak and D.E. Ellison: “USAF Stability and Control DATCOM”. McDonnell Douglas Airplane Cy., Oct. 1960, Revised Aug. 1968.
5. Anon.: “Subsonic lift-dependent drag due to wing trailing vortices”. R.Ae.S. Data Sheets, “Wings ” 02. 01. 02, 1965.