In this study an attempt to examine the dependence between the productivity of core journals and the shape of the distribution curve in the upper section is made. For this purpose, the impact of the core journal productivity increase over an extended time interval was investigated. As a referent point in relation to which the changes were followed, equalized inverse relationship between the core and periphery in terms of the number of journals and the number of papers published in them in a given subject field has been hypothesized. The degree to which a particular set of data conforms to that relationship expressed as , is taken as an indicator of the changes in the core/periphery relation. The applicability of Lotka's exponent in the journal productivity context is also discussed.