Artikel Jurnal
Doorn, Jacques van, author
Faculty of Social Sciences, Erasmus University Rotterdam, 1983
Buku Teks
Kitchin, C.R., author
CRC Press, Taylor & Francis Group, 2009
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Cochran, William G., author
John Wiley & Sons, 1977
Buku Teks
Cochran, William G., author
John Wiley , 1963
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