I would like to know if anyone has an electronic copy of the following paper:
"Holmgren, E.: Über Systeme von linearen partiellen Differentialgleichungen. Översigt Vetensk. Akad. Handlingar 58, 91–105 (1901)"
In my search, the best result I found was the (possible) statement of the main result of this article which can be found in the following article: https://people.kth.se/~haakanh/publications/Hed-MZ2.pdf. More precisely,
Theorem (Holmgren) Suppose $I$ is a real-analytic nontrivial arc of $\partial \Omega$. Then if $u$ is smooth on a planar neighbohood $\mathcal{O}$ of $I$ and $\Delta^N u=0$ holds on $\mathcal{O} \cap \Omega$ with $\partial_{n}^{j-1}|_I=0$ for $j=1, \dots, 2N$, then $u(z)=0$ on $\mathcal{O} \cap \Omega$, provided that the open set $\mathcal{O} \cap \Omega$ is connected.
Any information is welcome, for example, if this article is published in a book.