Pounds, Norman J. G., author
Silver Burdett, 1980
Buku Teks
Spidchenko, K.
Progress , 1972
Buku Teks
Mackinnon, Danny, author
Pearson, Prentice Hall, 2007
Buku Teks
Mackinnon, Danny, author
Routledge, 2019
Buku Teks
Stamp, L. Dudley (Laurence Dudley), 1898-1966, author
Methuen, 1950, 1952, 1967
Buku Teks