ที่มา : http://prp.trf.or.th/trf-policy-brief/%E0%B8%9C%E0%B8%A5%E0%B8%81%E0%B8%A3%E0%B8%B0%E0%B8%97%E0%B8%9A%E0%B8%82%E0%B8%AD%E0%B8%87%E0%B8%AA%E0%B8%B1%E0%B8%87%E0%B8%84%E0%B8%A1%E0%B8%9C%E0%B8%B9%E0%B9%89%E0%B8%AA%E0%B8%B9%E0%B8%87%E0%B8%AD/