3National Research Council (2011 ). Assessing 21st Century Skills : Integrating Research Findings [ EB/OL]. http ://researchnetwork. pearson.com/wp-content/uploads/Assessing_21 st_Century_Skills_NCME. pdf; Novak, J. D. An Approach to the Interpretation and Measurement of Problem Solving Ability. Science and Education, 1961, (2).
4Stuessy, C. L. Path analysis : A Model for the Development of Scientific Reasoning Abilities in Adolescents. Journal of Research in Science Teaching, 1989, ( 1 ).
