อ้างอิง

http://www.oknation.net/blog/nun2504/page78

http://www.koratdailynews.com/2012/08/13/

users1.jabry.com/trainingcenter2/parwatsakon3.pdf

http://e-book.ram.edu/e-book/inside/html/dlbook.asp?code=PE291

http://www.indumestic.com/?paged=2