EX6.หนังสือ2เล่ม

1.http://www.oie.go.th/sites/default/files/attachments/IndustBasicKnowledge/Master_11.pdf

2.https://drive.google.com/open?id=1oPTD5kL7vqS4OEHJiMoYMSY2T-iUfAd1