Fucilla, Joseph G.
Follett Publishing Company, 1964
Buku Referensi
Payne, Stanley G.
W.W. Norton, 1970
Buku Teks SO
Cronin, A.J.
Bantam Books, 1957
Buku Teks SO
Eckersley, C.E. [Charles Ewart], 1892-1967
Longman, Green, 1953
Buku Referensi
London; Cassell LTD., 1978
Buku Referensi