a publishing company produce 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 on 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. draw the er diagram.