Represents a work (e.g. numerous editions of a book, article, etc.)
Inheritance: PersistedObject
 public Work Save(Work work)
 {
     using (var transaction = Database.Session.BeginTransaction())
     {
         Database.Session.SaveOrUpdate(work);
         transaction.Commit();
     }
     return work;
 }
 public WorkDetails(Work work)
 {
     Work = work;
     Identifiers = new List<LibraryIdentifier>();
     Authors = new List<Author>();
     Subjects = new List<Subject>();
     Categories = new List<Category>();
     Keywords = new List<Keyword>();
     Comments = new List<Comment>();
     CrossReferences = new List<Work>();
 }