The credibility of any source is gauged by looking at many things. To know whether the information is credible, the most important criteria are the vital tools in academic that evaluates the sources. First, is the author of the information, if the author is known from the previous publications, then you do not need to worry.
The material published is also essential there the materials that are used should not be over ten years. The purse of the source also matters, to ensure you are not biased always-used only viable sources.