[6316] On non-linear differential equations of the second order. III. The equation $$\ddot y - k\left( {1 - y^2 } \right)\dot y + y = b\mu k$$ cos (μt+α) for large k, and its generalizationscos (μt+α) for large k, and its generalizations

[6317] On non-linear differential equations of the second order: IV. The general equation $$\ddot y + kf\left( y \right)\dot y + g\left( y \right) = bkp\left( \varphi \right)$$ , φ=$t$+α, φ=$t$+α

[6318] 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

[6319] Über die Multiplikation der Kausalfunktionen in der Quantentheorie der Felder

[6320] The numbers of labeled colored and chromatic trees