Daniel, Moehar, author
Bumi Aksara, 2006
Buku Teks
John Newton author
Routledge , 1992
Buku Teks
Hennessy, Maurice N., author
Frederick A. Praeger, 1961
Buku Teks
Appraisal Institute, 2014
Buku Teks
Conant, James B., author
Harvard University Press, 1958
Buku Teks