Fraser, D.A.S., author
John Wiley & Sons, 1967
Buku Teks SO
Johnson, Palmer O., author
Prentice-Hall, 1953
Buku Teks SO
Montgomery, Douglas C., author
Gadjah Mada University Press, 1990
Buku Teks SO
Tippett, L.H.C., author
Williams and Norgate, 1952
Buku Teks
Yamane, Taro, author
New York University, 1967
Buku Teks