BSL. — 1972. — T. 67. — Fasc. 1. — P. 31–38.
In this paper Schindler established that animate root nouns in Indo-European could follow one of the two following declensional types: one with o-vocalism in the root in strong caseforms and genitive in -s and the other with e-vocalism in the root in strong caseforms and genitive in -os.