Plagiarism Checker with SMEs

With my design team we are working to build in best practices around ensuring the quality of our content. But we work with many different subject matter experts across multiple projects (I'm sure like many of you), and one thing that has come up for discussion is how we can prevent plagiarism or even accidental duplication of external content. For example, SMEs often give us Word Docs of content that we design into Rise modules, but how would we know if an SME just copies content from a website without referencing? Or even if it happens accidentally, such as someone copies something but forgets to reference the source. We would like to develop an easy system for checking for this since we are a small team with limited time/resources. Our Rise modules are also shared external to our organization, which is another reason we want to quality control content with a more public-facing audience.  

Does anyone have a good system for checking their Rise module content for plagiarism? One thought would be if I could download the PDF version of a Rise module and run it through some sort of free plagiarism checker. 

Thanks for the help and any suggestions for a good system that works!