Incoming Resources
- Penguin Books, Harmondsworth, Eng., New York, 1976, c1939
- Penguin Books, Harmondsworth, Eng., New York, 1976, c1962
- Penguin Books, Harmondsworth, Eng., New York, 1976, 1977 Printing
- Penguin Books, Harmondsworth, Eng., New York, 1950
- Penguin Books, Harmondsworth, Eng., New York, N.Y., 1976, c1962
- Penguin Books, Harmondsworth, Eng., New York, ©1981