[1811] Sur l'intégration des systèmes différentiels qui admettent des groupes continus de transformations

[1812] On non-linear differential equations of the second order: III. The equation $$\ddot y - k(1 - y^2 )\dot y + y = b \mu k cos (\mu t + \alpha )$$ for large$k$, and its generalizationsfor large$k$, and its generalizations

[1813] Perturbations of nonlinear systems

[1814] On the frequency of Titchmarsh’s phenomenon for ζ($s$)-V

[1815] On interpolation of compact operators