I know that the following statement is true, but I would like to find a reference for it so I don't have to write the proof. Do you guys have a reference?
Let $\Omega$ and $\Omega'$ be smooth manifolds and let $\mathcal V \subset \mathbb C T \Omega$ be an involutive fiber bundle. Let $f : \Omega \to \Omega'$ be a submersion and suppose that for all smooth sections $X$ of $\ker f_*$ and all smooth sections $Y$ of $\mathcal V$, it holds that $[X, Y]$ is a smooth section of $\mathcal V$, then $f_*(V)$ is an involutive subbundle of $\mathbb C T\Omega'$.
Any help would be greatly appreciated.