Insler Stanley. On proterodynamic root present inflection

Münchener Studien zur Sprachwissenschaft. — 1972. — Vol. 30. — p. 55-64.Insler argues that Indo-Iranian most likely possessed an active proterodymanic present which was uniformly built with lengthened-grade vocalism throughout the whole indicative-injunctive paradigm, and that the existence of such an active paradigm permits us to directly equate the whole system of proterodynamic present inflection with the whole system of sigmatic aorist inflection attested in that branch of Indo-European.