A sample of 80 Hungarian scientists, authors or co-authors of a total number of 6273 papers—published between 1930–1976—has been analysed. Citation data to eachpaper were collected form the 1964–76 SCI's by manual search. Citation counts were distinguished with respect to the following categories: (I) the set of cited authors has element(s) common with the set of citing authors (self citation), (II) condition I is not satisfied, but the cited author under study and at least one of the citing authors were co-authors prior to the publication of the cited paper, (III) none of the former criteria is satisfied. The yearly average citation frequency of a paper was not corrected for obsolescence, since there is no evidence that the decay of citation frequency with time is independent of the absolute citedness of the paper. Individual performance has been measured (a) by the sum of the vearly average typeIII fractional citation frequencies over all of the author's papers, (b) by the sum of the yearly average citation frequency normalized to one single-authored paper per year over the period of the author's activity, (c) by the same as ina, but summed up only over the most highly cited papers scattering upwards from the individual's own average, (d) by the fractional authorship, and (e) by the number of items in the author's publication list. The first three parameters seem to be applicable in measuring the utility of the individual's scientific contribution with slightly different emphasis on different aspects. These parameters are uncorrelated with those measuring the output of individuals.