APA (7th ed.) Citation

Thetford, O. G., Thetford, O., & Gray, P. L. (1968). Aircraft of the Royal Air Force since 1918 (4th ed.). Putnam.

Chicago Style (17th ed.) Citation

Thetford, Owen Gordon, Owen Thetford, and Peter Laurence Gray. Aircraft of the Royal Air Force Since 1918. 4th ed. London: Putnam, 1968.

MLA (8th ed.) Citation

Thetford, Owen Gordon, et al. Aircraft of the Royal Air Force Since 1918. 4th ed. Putnam, 1968.