What are three factors that could contribute to the credibility of a source and three that contribute to a source not being credible?

Various Communication sources, i'm not really certain i'm tired but Credibility refers to a person's perception of the truth of a piece of information

A source is probably credible if 1. it was published in a peer-reviewed scholarly journal 2.The author of the work has a degree such as a PhD 3. The material is fairly new A source might not be credible if 1. It comes from a personal blog 2. The author of the work seems to contradict themselves and generally seems to not know what they're talking about 3. The material is outdated