This best practice rule is a word of caution. Citations are truly powerful tools for building credibility, increasing your domain authority and boosting your SEO. But it is vital that you don’t overdo it. Too many links and too many citations can be a bad thing.
As a general rule of thumb, you should try to limit citations per piece of content to five to seven, including your own internal links. Your internal links per piece should really only amount to one or two as this is all that is needed. Citations are about balance. You need to back up your claims, but you shouldn’t create content that is stuffed with citations and links. Think of it like keyword stuff, it’s a dead and ultimately artificial SEO tactic that won’t result in any positive attention from Google.