Draw the ER diagram to design a system for a publishing company that produces scientific books on various subjects. The books are written by authors who specialize in one particular subject. The company employs editors who not necessarily being specialists in a particular area, each take sole responsibility for editing one or more publications.
A publication covers essentially one of the specialist subjects and is normally written by a single author. When writing a particular book, each author works with editor, but may submit another work for publication to be supervised by other editors. To improve their competitiveness, the company tries to employ a variety of authors, more than one author being a specialist in a particular subject.