1. Saying there is "plenty of literature" without citing any of it does not prove such literature exists, or that there is "plenty" of it.

2. Even we stipulate that there is "plenty of literature," that means nothing. There is "plenty of literature" on lots of things that are a bunch of hooey.

3. With no citations, there's no way to know exactly what this purported literature consists of, who produced it, or what their agenda was, among other things, much less evaluate its validity or quality.

Conclusion: the statement "There is plenty of literature available" is completely meaningless without additional information.