Taussig, F. W.
Macmillan, 1947
Buku Teks SO
Lovering, W.F.
Longmans, 1966
Buku Teks
Burgess, W. Randolph
Harper & Brothers , 1946
Buku Teks
Thomas, F.W.
University of Calcuta, 1942
Buku Teks SO
edited by Peter Newman, Murray Milgate and John Eatwell
Macmillan, 1992
Buku Referensi