-- Database schema
| publication : Publication_ID [ INT ] primary_key , Book_ID [ INT ] publication.Book_ID = book.Book_ID , Publisher [ TEXT ] , Publication_Date [ TEXT ] , Price [ INT ] | book : Book_ID [ INT ] primary_key , Title [ TEXT ] , Issues [ INT ] , Writer [ TEXT ] |
-- -- Show writers who have published a book with price more than 4000000.

SELECT T1.Writer FROM book AS T1 JOIN publication AS T2 ON T1.Book_ID  =  T2.Book_ID WHERE T2.Price  >  4000000;