Jeffrey Gitomer has a great series of little books like his Little Red Book of Sales Answers. Other superb books I'd recommend are Ian Altman's Upside Down Selling and Harry Beckwith's Selling the Invisible as well as Karl Albrecht's Service America.

My own book, Seal the Deal, could be useful to you as it distinguishes networking, marketing, and sales for a service professional and outlines a system for how to leverage the essential mindsets in each one for integrated action. It's not written specifically for CEOs, though, so you may not want that.

You might also check out Bill Cates' newest book: Beyond Referrals.

As for courses, there are a wide array of excellent offerings available on udemy.com on every topic under the sun!

You might also consider hiring an executive coach. Stanford just released a study about the value of CEOs having a coach: http://www.suzipomerantz.com/stanford-executive-coaching-study-reveals-most-ceos-want-coaching/