Porter, R. R. (1973). Defence and recognition. Butterworths; University Park Press.
Cita Chicago (17th ed.)Porter, R. R. Defence and Recognition. London, Baltimore: Butterworths; University Park Press, 1973.
Cita MLA (8th ed.)Porter, R. R. Defence and Recognition. Butterworths; University Park Press, 1973.
Atenció: Aquestes cites poden no estar 100% correctes.