In Theorem 14.37 of Variational Analysis by Rockafellar and Wets, it shows that for any normal integrand $f:T\times\mathbb{R}^n\to\overline{\mathbb{R}}$, the function $p:T\to\overline{\mathbb{R}}$ given by $$p(t):=\inf~f(t,\cdot)$$ is measurable, and the mapping $P:T\rightrightarrows\overline{\mathbb{R}}$ given by $$P(t):=\arg\min~f(t,\cdot)$$ is closed-valued and measurable.
According to the authors, many results in the book may be extended to spaces other than Euclidean. I am wondering is there a standard reference for the result if we replace $\mathbb{R}^n$ by a Polish (complete and separable metric) space?