Williams, B. (1978). A sampler on sampling. John Wiley and Sons.
Lua i Stíl Chicago (17ú heag.)Williams, Bill. A Sampler on Sampling. Nueva York: John Wiley and Sons, 1978.
Lua MLA (9ú heag.)Williams, Bill. A Sampler on Sampling. John Wiley and Sons, 1978.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.