Gottlieb, P. (1980). Agency (1st Sphere Books ed.). Sphere.
Cita Chicago (17th ed.)Gottlieb, Paul. Agency. 1st Sphere Books ed. London: Sphere, 1980.
Cita MLA (8th ed.)Gottlieb, Paul. Agency. 1st Sphere Books ed. Sphere, 1980.
Atenció: Aquestes cites poden no estar 100% correctes.