Lewis-Beck, Michael S., author
Sage, 1980
Buku Teks
Hanson, John Lloyd, author
MacDonald & Evans, 1975
Buku Teks
Fischer, Alice E., author
McGraw-HIll, 2001
Buku Teks
Kinsky, Roger, author
McGraw-Hill, 1981
Buku Teks
Meinel, Aden B., author
Addison-Wesley, 1979
Buku Teks