Duncan, Colin
John Wiley, 1981
Buku Teks
edited and compiled by Wolodymyr Maksymiw
Longman, 1990
Buku Referensi
Humphreys, Nick, author
Blackstone Press, 1999
Buku Teks
Paish, F.W. (Frank Walter)
Macmillan & Co. , 1950
Buku Teks
Goldstein, Joseph, author
Allen & Unwin, 1952
Buku Teks