Senelle, Robert
Ministry of Foreign Affairs and External Trade, 1979
Buku Teks SO
editor, Heide and Udo ernst Simonis
Otto Harrassowitz - Wiebaden , 1974
Buku Teks SO
Clough, Ray W., 1920-
McGraw-Hill , 1975
Buku Teks
Clough, Ray W., 1920-
McGraw-Hill, 1993
Buku Teks
Honjo, Eijiro
Russell & Russell, 1965
Buku Teks SO