Fried, Robert C.
Macmillan, 1968
Buku Teks
Hague, Rod.
Palgrave Macmillan , 2013
Buku Teks
Sargent, Lyman Tower
Cole Publishing, 1990
Buku Teks
Koopmans, Tim
Cambridge University Press, 2003
Buku Teks
Sargent, Lyman Tower
The Dorsey Press, 1981
Buku Teks