Retraction Note: Differences in cognitive functions between cytomegalovirus-infected and cytomegalovirus-free university students: a case control study.

We also recommend, whenever possible, to substitute the old version of our program Treept which was not user-friendly with other programs, e.g. with our new and more complex program for computing permutation tests for contaminated data[1]. After the publication of the article, J. Gottfried and H. Cigler brought to our attention that the results of the permutation tests for contaminated data in the explorative part of the study were incorrect. [Extracted from the article]