Flint, Colin, author
Taylor and Francis Group, 2018
Buku Teks
Mellor, Roy E. H.
Routledge, 1989
Buku Teks
Pounds, Norman J. G., author
McGraw-Hill, 1972
Buku Teks
Goblet, Y.M.
Prederick A. Praeger, 1955
Buku Teks
East, W. Gordon
Macmillan, 1975
Buku Teks