Try this search term: "black lives matter" and California -- with and without the quotation marks.
Limit to academic websites: "black lives matter" and California site:.edu
Limit to government websites: "black lives matter" and California site:.gov
Google Scholar provides a simple way to broadly search for scholarly literature. From one place, you can search across many disciplines and sources: articles, theses, books, abstracts and court opinions, from academic publishers, professional societies, online repositories, universities and other web sites. Google Scholar helps you find relevant work across the world of scholarly research.