The John HopkinsPress, 1964
Buku Teks
The World Bank , 1996
Buku Teks
Peffer, Nathaniel, author
University of Michigan Press, 1958
Buku Teks
David McKay Company, Inc., 1960
Buku Teks
Drozdzynski, Aleksander, author
Wydawnictwo Zachodnie, 1960
Buku Teks