A few years ago, Moz's Rand Fishkin ran a CTR case study which moved his site from #7 to #1 in less than 3 hours by sending clicks to his organic search results. These were real people, making real clicks. This was the first real indication that click through rate (CTR) was a factor that could heavily move organic results in the SERPs.
Here are some other published articles to consider:
Search Engine Journal:
Google’s Top Search Ranking Factors of 2016, According to Searchmetrics Study
WordStream:
Why You NEED to Raise Organic CTR’s (And How to Do It)
Moz:
The Impact of Queries, Long and Short Clicks, and Click Through Rate on Google's Rankings — Whiteboard Friday
Aside from buying website traffic there are a number of other things you can do on your own to increase your organic CTR and improve your SEO. Optimizing your Title and meta tags. Optimizing your on-page content to increase engagement. Optimizing your site structure, to ensure each page is highly matched to target specific (and, ideally, long-tail) keywords. And, of course, a million other things you can do from an SEO-perspective that are beyond the scope of these FAQs.