Morrison, Blake, author
Methuen , 1986
Buku Teks
Pinto, Vivian de Sola
Hutchinson's University Library, 1951
Buku Teks
Ward, A.C.
The English Language Book, 1928
Buku Teks
Falci, Eric, author
Cambridge University Press, 2015
Buku Teks
edited by Thomas Davidson
W. & R. Chambers, 1901
Buku Referensi