Vernadsky, George
At The Clarendon Press, 1959
Buku Teks
Vernadsky, George
Yele University Press, 1953
Buku Teks
Fennell, John
Longman, 1983
Buku Teks
Saunders, David, 1940-, author
Longman, 1992
Buku Teks
Laserson, Max M., author
Macmillan, 1950
Buku Teks