-- Database schema
| cites : cited_paper_id [ TEXT ] , citing_paper_id [ TEXT ] | paper : paper_id [ TEXT ] primary_key , class_label [ TEXT ] | content : paper_id [ TEXT ] content.paper_id = paper.paper_id , word_cited_id [ TEXT ] |
-- -- List all paper ID and its class type with more than 20 cited words.

SELECT DISTINCT T1.paper_id, T1.class_label FROM paper AS T1 INNER JOIN content AS T2 ON T1.paper_id = T2.paper_id GROUP BY T2.paper_id, T1.class_label HAVING COUNT(T2.word_cited_id) > 20;