Benham, Frederic, author
Pitman, 1947
Buku Klasik
Boulding, Kenneth E. (Kenneth Ewart), 1910-1993, author
John Wiley & Sons, 1950
Buku Teks
Boulding, Kenneth E. (Kenneth Ewart), 1910-1993, author
John Wiley & Sons, 1950
Buku Teks
Nordin, J.A., author
Prentice-Hall, 1954
Buku Teks
Gemmil, Paul F., author
Harper & Brothers, 1949
Buku Teks