AFRINAWATI A. THE EFFECT OF STUDENTS’ ATTITUDE AND PORTFOLIO ASSESSMENT TOWARDS THE ACHIEVEMENT OF STUDENTS’ SCIENCE PROCESS SKILL. JEP [Internet]. 2013Mar.30 [cited 2025Aug.6];4(1):12 -4. Available from: http://103.8.12.212:33180/unj/index.php/jep/article/view/2717