public void FillData()
        {
            #region Adding authors
            authors = new Author[6];
            Author author1 = new Author("Author1", "*****@*****.**", 'm', new Date(2, 10, 1985));
            Author author2 = new Author("Author2", "*****@*****.**", 'f', new Date(12, 4, 1974));
            Author author3 = new Author("Author3", "*****@*****.**", 'm', new Date(25, 5, 1978));
            Author author4 = new Author("Author4", "*****@*****.**", 'f', new Date(10, 11, 1965));
            Author author5 = new Author("Author5", "*****@*****.**", 'm', new Date(23, 5, 1997));
            Author author6 = new Author("Author6", "*****@*****.**", 'f', new Date(2, 10, 1998));
            authors[0] = author1;
            authors[1] = author2;
            authors[2] = author3;
            authors[3] = author4;
            authors[4] = author5;
            authors[5] = author6;

            #endregion
            #region Adding books
            books = new List <Book>();

            Book book1 = new Book("book1", new Author[] { author1, author2 }, 0, 5);
            book1.SetPublicationDate(new Date(10, 1, 2004));
            books.Add(book1);
            Book book2 = new Book("book2", new Author[] { author3, author2 }, 0, 5);
            book2.SetPublicationDate(new Date(22, 4, 1994));
            books.Add(book2);
            Book book3 = new Book("book3", new Author[] { author4, author2 }, 3.4, 5);
            book3.SetPublicationDate(new Date(14, 2, 1991));
            books.Add(book3);
            Book book4 = new Book("book4", new Author[] { author1, author5 }, 10.1, 5);
            book4.SetPublicationDate(new Date(23, 8, 1989));
            books.Add(book4);
            Book book5 = new Book("book5", new Author[] { author1, author6 }, 8.3, 5);
            book5.SetPublicationDate(new Date(10, 11, 2014));
            books.Add(book5);
            Book book6 = new Book("book6", new Author[] { author1, author3 }, 6.5, 5);
            book6.SetPublicationDate(new Date(15, 1, 2008));
            books.Add(book6);
            Book book7 = new Book("book7", new Author[] { author3, author2 }, 3, 5);
            book7.SetPublicationDate(new Date(18, 5, 1998));
            books.Add(book7);
            Book book8 = new Book("book8", new Author[] { author4, author2 }, 5, 5);
            book8.SetPublicationDate(new Date(5, 3, 2004));
            books.Add(book8);
            Book book9 = new Book("book9", new Author[] { author5, author6 }, 25.7, 5);
            book9.SetPublicationDate(new Date(1, 6, 2002));
            books.Add(book9);
            Book book10 = new Book("book10", new Author[] { author1, author2, author3 }, 15.7, 5);
            book10.SetPublicationDate(new Date(4, 1, 1988));
            books.Add(book10);
            Book book11 = new Book("book11", new Author[] { author1, author2, author4 }, 13.7, 5);
            book11.SetPublicationDate(new Date(10, 1, 1965));
            books.Add(book11);
            Book book12 = new Book("book12", new Author[] { author1, author2, author5 }, 12, 5);
            book12.SetPublicationDate(new Date(1, 4, 2014));
            books.Add(book12);
            Book book13 = new Book("book13", new Author[] { author1, author2, author6 }, 11, 5);
            book13.SetPublicationDate(new Date(10, 1, 1999));
            books.Add(book13);
            Book book14 = new Book("book14", new Author[] { author1, author4, author6 }, 9, 5);
            book14.SetPublicationDate(new Date(8, 8, 2008));
            books.Add(book14);
            Book book15 = new Book("book15", new Author[] { author1, author5, author3 }, 8, 5);
            book15.SetPublicationDate(new Date(10, 1, 2012));
            books.Add(book15);
            Book book16 = new Book("book16", new Author[] { author1 }, 30, 5);
            book16.SetPublicationDate(new Date(25, 4, 2004));
            books.Add(book16);
            Book book17 = new Book("book17", new Author[] { author3 }, 20, 5);
            book17.SetPublicationDate(new Date(26, 5, 1999));
            books.Add(book17);
            Book book18 = new Book("book18", new Author[] { author2 }, 16, 5);
            book18.SetPublicationDate(new Date(10, 10, 2000));
            books.Add(book18);
            Book book19 = new Book("book19", new Author[] { author4 }, 8, 5);
            book19.SetPublicationDate(new Date(9, 10, 2004));
            books.Add(book19);
            Book book20 = new Book("book20", new Author[] { author6 }, 7, 5);
            book20.SetPublicationDate(new Date(11, 1, 1989));
            books.Add(book20);

            #endregion

            #region link books and authors
            author1.SetBooks(new Book[] { book1, book4, book5, book6, book10, book11, book12, book13, book14, book15, book16 });
            author2.SetBooks(new Book[] { book1, book2, book3, book7, book8, book10, book11, book12, book13, book18 });
            author3.SetBooks(new Book[] { book2, book6, book7, book10, book17 });
            author4.SetBooks(new Book[] { book3, book8, book11, book14, book19 });
            author5.SetBooks(new Book[] { book4, book9, book12, book15 });
            author6.SetBooks(new Book[] { book5, book9, book13, book14, book20 });

            #endregion
        }