SELECT Publisher FROM publication GROUP BY Publisher HAVING COUNT(*)  >  1
Show publishers that have more than one publication.
[Schema (values) (types)]: | book_2 |  publication : publication_id (text) , book_id (number) , publisher (number) , publication_date (text) , price (text) | book : book_id (text) , title (number) , issues (number) , writer (text);