Source: Official Google Webmaster Central Blog [EN]: Making Review Rich Results more helpful
Learn how to add reviews and star ratings in your website to get Star ratings in Google search result pages (SERPs). It’s easy to get a star rating in Google Source: How to add stars in Google search results? [2019 Update] – Tring Web Design
Detailed step-by-step tutorial on how to get star ratings for your site to show up in Google’s main search results listings. Source: How to Get Star Ratings for Your Site in the Google Search Results
Want to give your site boost in search traffic with rich snippets and structured data? Learn how to use rich snippets on your WordPress site. Source: Beginner’s Guide: How to Use Rich Snippets in WordPress
Source: A Simple Guide To Rich Snippets For WordPress | Elegant Themes Blog