Wiroj Lakkhanaadisorn และ Udomsak Seenprachawong. (2013) A willingness to pay study of heritage interpretation : a case study of the historic city of Ayutthaya. National Institute of Development Administration:ม.ป.ท.Wiroj Lakkhanaadisorn และ Udomsak Seenprachawong. 2013. A willingness to pay study of heritage interpretation : a case study of the historic city of Ayutthaya. ม.ป.ท.:National Institute of Development Administration;Wiroj Lakkhanaadisorn และ Udomsak Seenprachawong. A willingness to pay study of heritage interpretation : a case study of the historic city of Ayutthaya. ม.ป.ท.:National Institute of Development Administration, 2013. Print.