Undefined reference in the ACM Latex Template

We are using the ACM Latex template for research papers at the university.
The problem was, that all has compiled fine. But I have received questionmarks instead of references and all references from the bib file (correct linked in the tex file) were given out with undefined reference.

There is no hint for any package requirement as an error message. The solution was the missing ACM related package texlive-acmart.

You can install it on openSUSE:
sudo zypper in texlive-acmart