Platts, John T., author
Sampson Low, Marston, 1959
Buku Referensi
edited by John Robert Colombo
Hurtig Publishers, 1978
Buku Teks
March, Robert H., 1937-, author
McGraw-Hill , 1978
Buku Teks
March, Robert H., 1937-, author
McGraw-HIll, 2003
Buku Teks
FitzGerald, Robert David, 1902-, author
Angus & Robertson, 1963
Buku Teks