Charinthip Hengkrawit และ Kanet Ponpetch. (2016) Functional Equations Characterizing the Tangent Function Over a Convex Polygon II. <i>Thai Journal of Science and Technology</i>, <i>5</i>(2), 113-118.Charinthip Hengkrawit และ Kanet Ponpetch. "Functional Equations Characterizing the Tangent Function Over a Convex Polygon II". Thai Journal of Science and Technology 5 (2016):113-118.Charinthip Hengkrawit และ Kanet Ponpetch. Functional Equations Characterizing the Tangent Function Over a Convex Polygon II. Thammasat University:ม.ป.ท. 2016.