Graham, Daniel A.
Heath , [1990]
Buku Teks
Soemarso
ESG, 1978
Buku Teks
Krishnamurti, B.V.
Oxford University Press, 1949
Buku Teks
Kaplan, A.D.H.
Brookings Institutions, 1959
Buku Teks
Aoki, Masahito
Stanford University, [date of publication not identified]
Buku Teks