Collis, Robert
Charles Scribner's Sons, 1961
Buku Teks
Aboyade, Ojetunji, author
Praeger, 1966
Buku Teks
Kane, Robert S.
Doubleday & Company, 1964
Buku Teks
John, Robert St
Time Incorporated, 1962
Buku Teks
Payne, Robert
William Heinemann, 1947
Buku Teks