Townsend, Camilla
Oxford University Press, 2017
eBooks
Prescott, William Hickling, 1796-1859
The Modern Library , [Date of publication not identified]
Buku Teks SO
Russell, Bertrand, 1872-1970
Avon Book Divition, 1930
Buku Teks SO
Pick, James B.
Westview , 1989
Buku Referensi
Donnelly, Thomas C.
The University of New mexico Press, 1953
Buku Teks