Hi there, I wonder if you can give me a hint. I am trying to understand how non-google review stars can appear within the SERPs. Example: Searching for the German business coaching provider “Intem” using the search phrase “intem verkaufstraining” - google displays a 4.5 star rating made up of 1.1.52 reviews. The point is: these reviews aren’t google reviews. They are gathered via a training feedback process that has been approved and verified by a quality certification institute (Zertifizierung von Qualitätsmanagementsystemen (ZQS)).
My question is: what does it take to build up a similar process, so that google approves these kind of reviews for displaying them in the SERPS.
I hope I made myself clear enough. In advance thanks a lot for your help.