http://www.thapra.lib.su.ac.th/objects/thesis/fulltext/snamcn/Nattaya_Koraneekij/fulltext.pdf
http://www.chanidservice.com/pdf/his_lao
http://human.bsru.ac.th/search/sites/default/files/files/varasan%20HU5.pdf
http://www.thapra.lib.su.ac.th/objects/thesis/fulltext/snamcn/Nattaya_Koraneekij/fulltext.pdf
http://www.chanidservice.com/pdf/his_lao
http://human.bsru.ac.th/search/sites/default/files/files/varasan%20HU5.pdf