Artikel Jurnal
Anthony, Robert N. (Robert Newton), 1916-2006, author
Harvard University, 1952
Buku Teks
Chorafas, Dimitris N., author
Reinhold Publishing Corporation, 1958
Buku Teks
Lawrence L. Bethel ... [et al.]
McGraw-Hill, 1945
Buku Teks
by James L. Riggs ... [et al.]
McGraw-Hill, 1979
Buku Teks