Snedecor, George W., author
The Iowa State University Press, 1950
Buku Teks
Snedecor, George W., author
The Iowa State University Press, 1982
Buku Teks
Mayer, Joseph Edward, author
John Wiley & Sons, 1977
Buku Teks
Edwards, Allen L., author
Rinehart and Winston , 1958
Buku Teks
Pressat, Roland, author
Methuen, 1978
Buku Teks