http://supply.dusit.ac.th/e_bidding/e_bidding2562/e_bidding/1_draft/e_bid47611_1.pdf
http://supply.dusit.ac.th/e_bidding/e_bidding2562/e_bidding/1_draft/e_bid47611_2.pdf
http://supply.dusit.ac.th/e_bidding/e_bidding2562/e_bidding/1_draft/e_bid47611_3.pdf