Fucilla, Joseph G.
Follett Publishing Company, 1964
Buku Referensi
Eckersley, C. E. (Charles Ewart), 1892-1967
Longmans, Green and Co., 1953
Buku Referensi
London; Cassell LTD., 1978
Buku Referensi
Artikel Jurnal
Waterland, Liz
The Thimble Press, 1995
Buku Teks