By the number. Largest U.S. locum tenens staffing firms. Ranked by estimated 2010 U.S. temporary staffing revenue ($ millions).
D004465:Economic Competition / Q000145:classification*; D006296:Health Services / Q000191:economics; D006801:Humans; D010561:Personnel Staffing and Scheduling / Q000191:economics*; D014481:United States; D000078329:Workforce