World Bank, 1999
Buku Teks
Bulgarelli, Jose Francisco Aguilar
Foreign Languages Publishing House, 1984
Buku Teks
Schwindt-Bayer, Leslie A. author
Cambridge Univ. Press, 2017
Buku Teks
Fowler, Robert Booth, author
Praeger, 1985
Buku Teks
Abcarian, Gilbert
Charles Seribner's, 1970
Buku Teks