Table schema:
CREATE TABLE table_name_18 (sponsor_s_ VARCHAR, _number_of_cosponsors VARCHAR, date_introduced VARCHAR)

Question: Who was the sponsor for the bill introduced February 28, 2005 with cosponsors less than 200?
SQL: SELECT sponsor_s_ FROM table_name_18 WHERE _number_of_cosponsors < 200 AND date_introduced = "february 28, 2005"