Williamson, James A., author
Macmillan, 1962
Buku Teks
Badan Pusat Statistik, 2008
Buku Referensi
Marseille, Jacques, author
Paris : Editions Albin Michel, 2005
Buku Teks
Marseille, Jacques, author
Paris: Albin Michel, [2005]
Buku Teks
Bonea, Amelia, author
Oxford University Press, 2016
eBooks