Johnson, K. (2001). Problem solving strategies: Crossing the river with dogs and other mathematical adventures (2nd ed.). Key Curriculum Press.
Chicago-referens (17:e uppl.)Johnson, Ken. Problem Solving Strategies: Crossing the River with Dogs and Other Mathematical Adventures. 2nd ed. Emeryville, CA: Key Curriculum Press, 2001.
MLA-referens (9:e uppl.)Johnson, Ken. Problem Solving Strategies: Crossing the River with Dogs and Other Mathematical Adventures. 2nd ed. Key Curriculum Press, 2001.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.