Ford, Kenneth W.
Blaisdell Publishing, 1968
Buku Teks
Kompaneyets, A.S.
Peace Publishers, 1961
Buku Teks
Name, F. W. van, author
Prentice-Hall, 1966
Buku Teks
Weber, Robert L., author
McGraw-Hill, 1959
Buku Teks
Sears, Francis W. (Francis Weston), 1898-1975, author
Addison-Wesley, 1960
Buku Teks