user: Question: what's the author / editor / source with world ranking (1) being 73rd
Columns: ['Index (Year)', 'Author / Editor / Source', 'Year of publication', 'Countries sampled', 'World Ranking (1)', 'Ranking L.A. (2)']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Environmental Performance (2008)', 'Yale University', '2008', 149.0, '32nd', '5th']
SQL:

assistant: SELECT "Author / Editor / Source" FROM "Table" WHERE "World Ranking (1)" = '73rd';