Tivy, Joy, author
Longman Scientific & Technical, 1992
Buku Teks
Buku Teks
Hanks, Lucien M
Aldine Atherton, 1972
Buku Teks
Wojciechowski, Jerzy A., author
Council for research in values and philosophy, [Date of publication not identified]
Buku Teks SO
Odum, Eugene Pleasants, author
Saunders College, 1983
Buku Teks