Campbell, George L., author
Routledge, 1995
Buku Referensi
Campbell, George L., author
Routledge, 1998
Buku Teks
Bray, R.G.A. de, author
J.M. Dent & Sons, 1951
Buku Teks
Wurm, Stephen Adolphe, 1922-, author
Narr, 1982
Buku Teks
Routledge, 1998
Buku Teks