COCHRAN, W. G. (1977). Sampling Techiques William G. Cochran. John Wiley & Sons.
Lua i Stíl Chicago (17ú heag.)COCHRAN, William G. Sampling Techiques William G. Cochran. John Wiley & Sons, 1977.
Lua MLA (8ú heag.)COCHRAN, William G. Sampling Techiques William G. Cochran. John Wiley & Sons, 1977.
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