Thet zaw Win และ Chavalek Vanichavetin. (2011) Study on the spiral curve in highways and interchange ramps. Kasetsart University:ม.ป.ท.Thet zaw Win และ Chavalek Vanichavetin. 2011. Study on the spiral curve in highways and interchange ramps. ม.ป.ท.:Kasetsart University;Thet zaw Win และ Chavalek Vanichavetin. Study on the spiral curve in highways and interchange ramps. ม.ป.ท.:Kasetsart University, 2011. Print.