Tobin, James
Edward Elgar , 1999
Buku Teks
Hansen, Alvin H. (Alvin Harvey), 1887-1975, author
MacGraw-Hill , 1947
Buku Teks
Andrerson, James E., author
Addison-Wesley, 1970
Buku Teks
Reuss, Henry S., author
McGraw-Hill, 1964
Buku Teks
edited by Herbert C. Morton
Brookings Institution, 1965
Buku Teks