Erickson, Roy V., author
Allyn and Bacon, 1985
Buku Teks
Unesco, 1985
Buku Teks
Chou, Ya-Lun
Rinehart and Winston, 1969
Buku Teks
Downie, N. M.
Harper & Row, Pub., 1974
Buku Teks
Dixon, Wilfrid J. (Wilfrid Joseph), author
McGraw-Hill , 1983
Buku Teks