Aitken, A.C., author
Oliver and Boyd , 1974
Buku Teks
Lindgren, Bernard W., author
Macmillan, 1968
Buku Teks
Snedecor, George W., author
Iowa State University Press, 1989
Buku Teks
Snedecor, George W., author
The Iowa State University Press, 1980
Buku Teks
Snedecor, George W., author
The Iowa State University Press, 1950
Buku Teks