Wittchen, H.-U. Max Planck Institute of Psychiatry, Max Planck Society;
Sartorius, N., Üstün, T. B., Costa e Silva, J. A., Goldberg, D., Lecrubier, Y., Ormel, H., et al. (1993). An international study of psychological problems in primary care. Preliminary report from the World Health Organization Collaborative Project on "Psychological Problems in General Health Care". Archives of General Psychiatry, 50, 819-824.