Herr, T., & Johnson, K. (1994). Problem solving strategies: Teacher's resource book and answer key. Key Curriculum Press.
Citazione stile Chigago Style (17a edizione)Herr, Ted, e Ken Johnson. Problem Solving Strategies: Teacher's Resource Book and Answer Key. Berkeley, Calif: Key Curriculum Press, 1994.
Citatione MLA (9a ed.)Herr, Ted, e Ken Johnson. Problem Solving Strategies: Teacher's Resource Book and Answer Key. Key Curriculum Press, 1994.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.