Howell, W. G., & Brent, D. M. (2013). Thinking about the presidency: The primacy of power. Princeton University Press.
Lua i Stíl Chicago (17ú heag.)Howell, William G., agus David Milton Brent. Thinking About the Presidency: The Primacy of Power. Princeton: Princeton University Press, 2013.
Lua MLA (9ú heag.)Howell, William G., agus David Milton Brent. Thinking About the Presidency: The Primacy of Power. Princeton University Press, 2013.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.