Essentially "Critical Reading" means researching a topic from different sources and viewpoints in order to make an informed opinion about a piece of information. It is the ability to question and analyse information which we receive before accepting it as fact. It is important to understand that information in a text may be one author's personal viewpoint or opinion. It is therefore logical that we should challenge this opinion and research its authenticity.

By checking your information is cited by more than one author, you know there is strength and truth in your information. I also think it proves the information is not bias or an example of persuasive writing on behalf of the author.
Also I think it is extremely important to ensure your information is coming from reliable resources. Take the time to make sure the author, publisher, year of publication etc can be found. These bits of information validate the research.