The sources which are not considered appropriate for the academic research are generally termed as non-credible sources. These sources generally include sources for which the credibility of the author is either questionable or the source application of the research is limited.
Explanation:
Some general non-credible sources include
out-of-date materials (published over 10 years ago);
posts from social networks
blogs;
research articles without citations;
websites ending in .com, .org, .net etc.
websites with articles such that their author's credibility is unknown.
