Watzlawick, P., & weakland, J. H. (1974). Change: Principles of problem formation and problem resolution (ed.). W. W. Norton & company Inc..

Watzlawick, Paul, and John H. weakland. Change: Principles of Problem Formation and Problem Resolution. ed. New York: W. W. Norton & company Inc., 1974.

Watzlawick, Paul, and John H. weakland. Change: Principles of Problem Formation and Problem Resolution. ed. W. W. Norton & company Inc., 1974.