Perplexity is the strongest fit for verifying statements against primary sources because it searches the live web and returns cited links alongside every answer, letting you trace each claim back to its origin. You can paste a statement, ask Perplexity to find primary sources that confirm or contradict it, and then follow the provided citations directly. Elicit is a better choice when the statements involve academic or scientific claims, since it searches peer-reviewed literature and surfaces paper abstracts with direct links. NotebookLM works well if you already have a set of primary source documents and want to cross-check statements against that specific corpus rather than the open web.