Scheaffer, R. L., Mendehall, I., & Ott, L. (1996). Elementary survey sampling. Duxbury Press.
Lua i Stíl Chicago (17ú heag.)Scheaffer, Richard L., III Mendehall, agus Lyman Ott. Elementary Survey Sampling. Belmont: Duxbury Press, 1996.
Lua MLA (9ú heag.)Scheaffer, Richard L., et al. Elementary Survey Sampling. Duxbury Press, 1996.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.