HARRISON. E. R. (2012). FRANK MODERN CERTIFICATE BIOLOGY FOR MIDDLE SCHOOL WORKBOOK CLASS- 6 ( 2013- 14 ). FRANK BROS.
Čikaški stil citiranja (17. izdanje)HARRISON. E. R. FRANK MODERN CERTIFICATE BIOLOGY FOR MIDDLE SCHOOL WORKBOOK CLASS- 6 ( 2013- 14 ). FRANK BROS, 2012.
MLA način citiranja (9. izdanje)HARRISON. E. R. FRANK MODERN CERTIFICATE BIOLOGY FOR MIDDLE SCHOOL WORKBOOK CLASS- 6 ( 2013- 14 ). FRANK BROS, 2012.
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