Bookkeeping for companies with Investors + Common Stock + Preferred Stock

Hi everyone,

I'm a self-employed bookkeeper and consultant, who's been in the business for around 30 years. (20 on my own.) I've served primarily as a corporate specialist, or as the sole bookkeeper for small businesses. The consultant side of my business has focused on small businesses who do not have a trained bookkeeper in place, and who need education and help getting their books maintained correctly.

Over the past year or so, I've gained some sub-clients who are FinTech startups and the like, who have investors and stock. This is a realm with which I'm very unfamiliar. Does anyone have any good resources for education on company stock: the various types, and the bookkeeping/accounting of it all?

Thanks!