Cline, William R.
Praeger, 1972
Buku Teks
Gordon, Lincoln
Harvard University Press, 1963
Buku Teks
edited by Egbert De Vries, Jose Medina Echavarria
UNESCO, 1967
Buku Teks
edited by Werner Baer and Isaac Kerstenetzky
Richard D. Irwin, 1964
Buku Teks
edited by Howard S. Ellis and Henry C. Wallich
Macmillan, 1963
Buku Teks