Collier, P. (2007). The bottom billion: Why the poorest countries are failing and what can be done about it. Oxford University Press.
Lua i Stíl Chicago (17ú heag.)Collier, Paul. The Bottom Billion: Why the Poorest Countries Are Failing and What Can Be Done About It. Oxford ; New York: Oxford University Press, 2007.
Lua MLA (8ú heag.)Collier, Paul. The Bottom Billion: Why the Poorest Countries Are Failing and What Can Be Done About It. Oxford University Press, 2007.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.