What is the structure of the document with the least number of accesses?
SELECT t2.document_structure_description FROM documents AS t1 JOIN document_structures AS t2 ON t1.document_structure_code  =  t2.document_structure_code GROUP BY t1.document_structure_code ORDER BY count(*) DESC LIMIT 1
SELECT t2.document_structure_description FROM documents AS t1 JOIN document_structures AS t2 ON t1.document_structure_code  =  t2.document_structure_code GROUP BY t1.document_structure_code ORDER BY count(*) DESC LIMIT 1
[{'document_structure_description': 'Author section'}]