Shavelson, Richard J.
Allyn and Bacon , 1988
Buku Teks SO
Erickson, Bonnie H.
Open University Press, 1977
Buku Teks SO
Gravetter, Frederick J.
Wadsworth and Cengage Learning, 2009
Buku Teks SO
Knoke, David
Thomson, 2002
Buku Teks SO
Howell, David C.
Thomson Higher Education, 2004
Buku Teks SO