When it comes to using the phrase "referred to" in a document or conversation, it can sometimes feel repetitive. However, there are a plethora of synonyms to switch up the language and convey the same meaning. Some alternatives include: mentioned, alluded to, cited, indicated, pointed out, made reference to, named, suggested, recommended, and brought up. Choosing the right synonym depends on the context and tone of the document or conversation. Using a mix of these synonyms will not only add variety but also maintain reader engagement.