Buku Teks
editor in chief, Charles A. Ford
Encyclopedia Britannica Educational Corporation, 1969
Buku Referensi
consultant editor, D.E. Hathway
Harrap, 1985
Buku Referensi
de Vries, Louis, author
McGraw-Hill, 1959
Buku Referensi
de Vries, Louis, author
McGraw-Hill, 1951
Buku Referensi