Born produced a theory of collision phenomena in which electrons certainly are particles but then the... this had to be reconciled with wave mechanics, and he produced a complete theory of collisions and at the same time he introduced the important concept of the probability interpretation of the Schrödinger wave function; the absolute square of the wave function gives you the probability of finding the electron at a certain point or with a certain momentum.

[Q] And you studied that paper as...

I studied that paper very carefully as it came out.

[Q] And there is a second paper which appears in the Göttingen Nachrichten which you then also study.

In the second paper he applied the theory to the elastic and inelastic scattering of electrons by hydrogen atoms, and that became the basis of one of my papers, in fact one I consider to be quite an important paper, which I used for [my] Habilitation. In Germany, after taking a Doctor's degree, you are still not entitled to teach at the university; you had to take a second exam and especially you had to submit a more advanced paper for Habilitation. I did that in 1930 after having taken my Doctor's degree in 1928.