1. Bohr N. Philosophical Magazine 6 30 : 581 (1915).
2. Bohr N. Philosophical Magazine 6 25 : 10 (1913).
3. FOWLER, R.H., Contrtbutions to the theory of the motion of a-partocles through matter Part II, Ionizations, PROCEEDINGS OF THE CAMBRIDGE PHILOSOPHICAL SOCIETY 21: 531 (1923).
4. FOWLER, R.H., Contributions to the theory of the motion of alpha-particles through matter Part I, Ranges, PROCEEDINGS OF THE CAMBRIDGE PHILOSOPHICAL SOCIETY 21: 521 (1923).
5. Glasson T. L. Philosophical Magazine 6 22 : 647 (1911).