Ramsey, GC
Collins , 1968
Buku Teks
Christie, Agatha, 1890-1976, author
Gramedia Pustaka Utama, 2016
Buku Teks
Christie, Agatha, 1890-1976, author
Gramedia Pustaka Utama, 2019
Buku Teks
Buijnsters, P.J.
Martinus Nijhoff, 1984
Buku Teks
Ramsey
John Wiley & Sons, 1994
Buku Referensi