EOF
select_papers_by_name => <<'EOF',
SELECT * FROM papers WHERE file_name = ?;
+EOF
+ select_papers_by_pmid => <<'EOF',
+SELECT * FROM papers JOIN bibtex ON papers.file_name = bibtex.file_name WHERE bibtex.pmid = ?;
EOF
select_papers_by_name_like => <<'EOF',
SELECT * FROM papers WHERE file_name LIKE ?;