Let $K$ be a compact neighborhood in $\mathbb R^n$, $Z=X+Y$ are (non-vanishing if necessary) smooth vector fields on $K$. Denote by $e^{sZ}p$ an integral curve of $Z$ with initial point $p=e^{0Z}p\in K$ and a terminal point $q=e^{tZ}p\in K$. Then for any $\varepsilon>0$ there exists a large enough natural number $N$ such that
$$||(e^{\frac{s}{N}X}e^{\frac{s}{N}Y})^Np - e^{sZ}p||<\varepsilon$$
for all $0<s<t$.
I am looking for a reference for this statement (preferably a textbook)