Anthony, Robert Newton, 1916-2006
Harvard University, 1952
Buku Teks
Chorafas, Dimitris N.
Reinhold Publishing Corporation, 1958
Buku Teks
by Lawrence L. Bethel ... [et al.]
McGraw-Hill, 1962
Buku Teks
Lawrence L. Bethel ... [et al.]
McGraw-Hill, 1945
Buku Teks
Lundy, James L.
Eurasia Publishing House, 1968
Buku Teks