1984'6, p.118
Dubov I. G. , Smirnov L. M.
Construction of bipolar and unipolar scales for differential estimation of personality qualities in others

Factor analysis tends to reduce to a minimum the number of dimensions used to describe the personality of the other. It can not be used therefore whenever it is needed to quantitatively analyze the whole scope of perception of a particular dimension of the personality. In the authors' experiment a theory of fuzzy sets has been used for description of subjective opinions. As a result a set of 70 adjectives pertaining to "flexibility" as a personality quality have been broken into II clusters presenting different aspects of the corresponding notion.