610601_วิจัยบทที่ 2.pdf

http://webkc.dede.go.th/testmax/sites/default/files/610601_%E0%B8%A7%E0%B8%B4%E0%B8%88%E0%B8%B1%E0%B8%A2%E0%B8%9A%E0%B8%97%E0%B8%97%E0%B8%B5%E0%B9%88%202.pdf