Most information sources clearly indicate who is responsible for the work. Others, eg web pages, newspaper articles, give no indication of authorship/responsibility.
Without the basic knowledge of the author of a work, it is impossible to determine its authority.
Who is the author?
Most scholarly publications will list the author's qualifications and affiliated institution or organisation.
Some web pages clearly indicate who compiled or produced the information, usually in a link to About us, or About this site.
Other publications give no indication of authorship or responsibility. If you cannot determine who the author is, or their level of expertise, you might reconsider the authority of the resource