9Schmitz N, Hartkamp J, Kiuse G H, el al. The Symptom Check - List - 90 - R. (SCL. - 90 - R): A German validation study. Quality of Life Research, 2000(9): 185- 193.
10Helm D, Eis D. Subgrouping outpatients of an envimnrnental medicine unit using SCL - 90 - R and cluster analysis. International Journal of Hygiene and Environmental Health, 2006(11 ) : 1 - 13.