Cross referencing is a name I have tagged to a useful skill in which you take the same information and check different sources to make sure it is valid.  For HiH, I usually cross reference the notes I take in the lesson to the notes I take in the book.  If there are any discrepancies or invalid information, I usually go with the more valid source.  In this case, I usually go with the lessons.  However, there are rarely any mistakes because the lessons and textbooks have been edited so thoroughly.  Knowing this, cross referencing can be used to find out more information on the exact same topic.  This can add. Ore detail to your essays and generally expand your knowledge.  Furthermore, cross referencing can increase your knowledge on a subject.  By reviewing something you already know, the information will be reinforced in your mind.  Cross referencing can include looking at multiple source, but also other people's work.  There is no shame in looking at other's works if it improve your own and no plagiarism is taking place.  Journal from a Cluttered Mind by Sophie Loftus-Mannion is an excellent source for other work.  Please keep this in mind next time you write an essay!