Obruchev, Vladimir, author
Foreign Languages, 1959
Buku Teks
Montgomery, Carla W., author
Wm. C. Brown , 1989
Buku Teks
Rogers, John J.W., author
Harper & Row, 1966
Buku Teks
Bell, F.G., author
Butherworth Heinemman, 1976
Buku Teks
Gilluly, James, author
W.H. Freeman, 1959
Buku Teks