Kuykendall, Ralph S., author
Prentice-Hall, 1961
Buku Teks
Johnson, Miranda, author
Oxford University Press, 2016
eBooks
Kemp, Jeremy Hugh.
Social Science Review, Social Science Association Press of Thailand, 1969
Buku Teks
Eggleston, H.G.
Cambridge University Press, 1963
Buku Teks
Raggatt, H.G.
Lansdowne Press, 1968
Buku Teks