Great Briain. Department of Education and Science. Assessment of Performance Unit & Johnson, S. (1989). National assessment: The APU science approach. Her Majesty Stationery Office.
Chicago-viite (17. p.)Great Briain. Department of Education and Science. Assessment of Performance Unit ja Sandra Johnson. National Assessment: The APU Science Approach. London: Her Majesty Stationery Office, 1989.
MLA-viite (9. p.)Great Briain. Department of Education and Science. Assessment of Performance Unit ja Sandra Johnson. National Assessment: The APU Science Approach. Her Majesty Stationery Office, 1989.
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