In this paper we first pay attention to the inaccessibility of literature via keywords, UDC-codes, etc. Creative nosing is much more efficient and effective. As a main cause of this inaccessibility is pointed at the fact that most publications were made with an other main-purpose, and thus were there "by-products" not expressed in title or in summary. In chapter 2 some aspects of opinions-research are discussed. In chapter 3 some problems with the interpretation of model coefficients are discussed.
Abstract