Working from a bibliography in another aper is not plagiarism. It's actually a pretty good research technique. As you read those papers, check their bibliographies, too, and soon you will have pretty thorough coverage.
Do note that you cannot just plop those 50-60 or so references into your own bibliography but do nothing else. That's called reference padding and is academic misconduct. You have to actually read the papers. When you do that, you may find that some of them don't fit your needs as well as you may have at first thought.