Artikel Jurnal
The Queen's Printer, 1963
Buku Teks
Stephanus Munadjat Danusaputro, author
Binacipta, 1981
Buku Teks
McGovern, William M., author
University of North Carolina Press, 1939
Buku Teks
Myrdal, Gunnar, 1898-, author
Gerald Dukworth & Co. Ltd., 1957
Buku Teks