Persson, B., Werdelin, I., & Wilmo, K. (1968). Experimental studies of the use of abstract and concrete concepts in problem solving. Department of Educational and Psychological Research, School of Education.
芝加哥风格引文Persson, B., I. Werdelin, 与 K. Wilmo. Experimental Studies of the Use of Abstract and Concrete Concepts in Problem Solving. Malmo, Sweden: Department of Educational and Psychological Research, School of Education, 1968.
MLA引文Persson, B., et al. Experimental Studies of the Use of Abstract and Concrete Concepts in Problem Solving. Department of Educational and Psychological Research, School of Education, 1968.
警告：这些引文格式不一定是100％准确.