Paneeta Nitayaphorn และ Wirote Aroonmanakun. (2009) A reference grammar of radiotelephony in air-ground communication. Chulalongkorn University:ม.ป.ท.Paneeta Nitayaphorn และ Wirote Aroonmanakun. 2009. A reference grammar of radiotelephony in air-ground communication. ม.ป.ท.:Chulalongkorn University;Paneeta Nitayaphorn และ Wirote Aroonmanakun. A reference grammar of radiotelephony in air-ground communication. ม.ป.ท.:Chulalongkorn University, 2009. Print.