Наследование

abstract class Publication
    {
        public int ID { get; set; }
        public string Name { get; set; }
        public string Author { get; set; }
 
        public Publication(int id, string name, string author)
        {
            ID = id;
            Name = name;
            Author = author;
        }
        abstract public void Display();
    }
    class Library : Publication
    {
        List<Publication> publications = new List<Publication>();
 
        public Library(int id, string name, string author) 
            : base(id, name, author)
        {
        }
 
        public override void Display()
        {
            foreach (Publication publication in publications)
            {
                Console.WriteLine(publication);
            }
        }
    }
    
    class Book : Publication
    {
        bool is_Book = true;
        public Book (int id, string name, string author, bool isBook)
            : base(id, name, author)
        {
            is_Book = isBook;
        }
 
        public override void Display()
        {
            Console.WriteLine("It's a book");
        }
    }
    class Magazine : Publication
    {
        bool is_Magazine = true;
        public Magazine(int id, string name, string author, bool isMagazine)
            : base(id, name, author)
        {
            is_Magazine = isMagazine;
        }
 
        public override void Display()
        {
            Console.WriteLine("It's a magazine");
        }
    }
    class Newspaper : Publication
    {
        bool is_Newspaper = true;
        public Newspaper(int id, string name, string author, bool isNewspaper)
            : base(id, name, author)
        {
            is_Newspaper = isNewspaper;
        }
 
        public override void Display()
        {
            Console.WriteLine("It's a newspaper");
        }
    }
    class Fiction : Book
    {
        string genre;
        public Fiction(int id, string name, string author, bool isBook, string genre)
            : base(id, name, author, isBook)
        {
            genre = "fiction";
        }
    }
    class NonFiction : Book
    {
        string genre;
        public NonFiction(int id, string name, string author, bool isBook, string genre)
            : base(id, name, author, isBook)
        {
            genre = "non-fiction";
        }
    }
    class MagForTeens : Magazine
    {
        string magType;
        public MagForTeens(int id, string name, string author, bool isMagazine, string magType)
            : base(id, name, author, isMagazine)
        {
            magType = "for teenagers";
        }
    }
    class MagForGrannies : Magazine
    {
        string magType;
        public MagForGrannies(int id, string name, string author, bool isMagazine, string magType)
            : base(id, name, author, isMagazine)
        {
            magType = "for grannies";
        }
    }
    class LocalNewspaper : Newspaper
    {
        string newspaperType = "local news";
        public LocalNewspaper(int id, string name, string author, bool isNewspaper, string newspaperType)
            : base(id, name, author, isNewspaper)
        {
            newspaperType = "local news";
        }
    }
    class WorldwideNewspaper : Newspaper
    {
        string newspaperType = "worldwide news";
        public WorldwideNewspaper(int id, string name, string author, bool isNewspaper, string newspaperType)
            : base(id, name, author, isNewspaper)
        {
            newspaperType = "worldwide news";
        }
    }