N̄æothāng kānčhat tham rāingān kānwikhr̨o phonkrathop singw̄ætl̨̄om khrōngkān thīphak ʻāsai, b̨̄orikān chumchon, læ sathān thīphak tākʻākāt (Klum Ngān Khrōngkān B̨̄orikān Chumchon læ Thīphak ʻĀsai, K̨̄ong Wikhr̨o Phonkrathop Singw̄ætl̨̄om, Samnakngān Nayōbāi læ Ph̄æn Singw̄ætl̨̄om, Krasūang Witthayāsāt, Thēknōlōyī, læ Singw̄ætl̨̄om, 1999)
On system of analysing factors affecting environmental conditions of Thailand.