[Rationalization of literature coverage in special documentation].

Strategy for covering the building-up and up-to-date completion of a special documentation true is developed from the example given by the special documentation of literature on drugs included in the range of "Bayer" pharmaceutical products. The very expensive coverage system of primary literature can only be adapted to practical conditions and rationalised by making continual statistical analyses of the distribution of publications. The results of such an analysis are given. Tliey agree with the hypothesis that for publishing special literature there are specific threshold value's whose loga-rithms are almost normally distributed. On this basis it is possible to establish estimates for the actual extent of special literature able to be covered, as well as for the extra expenditure necessary for the perusal of primary literature if higher coverage quotas were required.