Russell, Richard Joel, author
May, 1960
Buku Teks
Wilson, E. Bright, author
McGraw-Hill, 1952
Buku Teks
Freedman, Paul, author
Public Affairs Press, 1950
Buku Teks
Ford, E. David, author
Cambridge University Press, 2000
eBooks
E. David Ford, author
Cambridge University Press, 2000
eBooks