ชมภู บ. Comparisons of Learning Achievements, Analytical Thinking Abilities, Satisfaction with Learning and Teaching, and Learning Retention in the Mathematics Learning Strand Entitled Trigonometrical Ratios of Matthayomsueksa 4 Students Using Courseware Geometer’s Sketchpad Approach (CGS) and the Conventional Teaching Approach. J.TNSU 2010, 2, 155-165.