*Reiss, K.; Schoenfeld, A.; Törner, G., eds.: Problem Solving Around the World? Sum- ming up the State of the Art. ZDM Mathematics Education (5-6)39 (2007), two issues. | *Reiss, K.; Schoenfeld, A.; Törner, G., eds.: Problem Solving Around the World? Sum- ming up the State of the Art. ZDM Mathematics Education (5-6)39 (2007), two issues. |