King, M. H., author
Oxford University Press, 1978
Buku Teks
Mackintosh, A.S.
Cambridge University Press , 1963
Buku Teks
United Nations , 1961
Buku Teks
Palvia, Chand Mal
Institute of Social Studies, 1953
Buku Teks
Anesaki, Masakaw
Charles E. Tutte Company, 1963
Buku Teks