simple Google search. Quick tip: If someone is an authority author, you'll most likely see that they have a strong social presence in a good amount of Google+ social circles, an active Twitter account, and a good amount of articles, as you don't become a great industry writer by writing five posts. Look for writers who create content that is interesting, accurate, useful, and engaging. Local These are sites like your Chamber of Commerce, local education sites, local news sites, trade organizations, charities, radio and news stations, etc. If you wanted to find out what was going on with something locally, think of which site you'd trust, and this is probably your local authority. To find these, you can simply search for topics like "my city news" and "my state school." Many times sites like your Chamber of Commerce will lead you to other great local authority sites through their own links, so make sure you check out any sections like "Related Links" or "Resources." Industry Whatever your industry, you probably know of a site or a few sites that you'd go to for relevant information. There may be sites such as umbrella organizations, certification agencies, governing bodies, etc. Searches such as "my industry" can bring these up but also force you to wade through loads of spam at times. Tacking on keywords like certification, agency, meeting, rules, laws, and annual conference may help you find these authorities. You can also easily use social media to find these. Many times,