Reliable publications generally include references to the sources of information included in the publication. This allows the reader to verify any information and, because a publication often only includes a brief portion of any source, to obtain additional information from the original source.
Authors can make mistakes and misinterpret details from an original source. So it does not hurt to verify that what the authors claim was stated in a reference was really stated in that reference.
Take note of the dates of publication of the reference sources. The publication itself may be published in the past year but, if the references are all more than ten years old, perhaps the author missed some recent discoveries or ideas.
A publication may include references that are unobtainable. This can be frustrating because then content from original sources may not be verifiable. Get help from a librarian to learn your options for obtaining the original source. However, do not be too quick to discount or ignore a new idea just because you cannot obtain the original source. The content may be true. Unobtainablility raises questions but does not in itself demonstrate falsehood.
Albert Einstein's On the Electrodynamics of Moving Bodies was published in 1905 in Germany and introduced his theory of relativity. It contained zero references because the idea was entirely original.
