Doble, Marion
Martinus Nijhoff, 1960
Buku Referensi
Tiger Books International, 1994
Buku Referensi
New York Oxford University Press 1998,
Buku Referensi
edited by Susie Beattie and Rachel Smith
Harper and Collins, 2011
Buku Referensi
Agrawal, Giriraj Sharan
Diamond pocket books, 2001
Buku Referensi