-- 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 ] |
-- -- What is the most cited word? How many papers was that word cited in?

SELECT word_cited_id, COUNT(paper_id) FROM content GROUP BY word_cited_id ORDER BY COUNT(word_cited_id) DESC LIMIT 1;