Johnson, K. (2001). Problem solving strategies: Crossing the river with dogs and other mathematical adventures (2nd ed.). Key Curriculum Press.
Παραπομπή σε μορφή Chicago (17η εκδ.)Johnson, Ken. Problem Solving Strategies: Crossing the River with Dogs and Other Mathematical Adventures. 2nd ed. Emeryville, CA: Key Curriculum Press, 2001.
Παραπομπή σε μορφή MLA (9th εκδ.)Johnson, Ken. Problem Solving Strategies: Crossing the River with Dogs and Other Mathematical Adventures. 2nd ed. Key Curriculum Press, 2001.
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