Indo-European offers a wide variety of infinitive formations, many of which are shared by several of the dialects, and all of which appear to reflect earlier verbal nouns. The literature includes considerable discussion on the etymological origins of individual infinitive endings, but little on intermediate developments which may account for the disparate systems of the historical languages. This paper suggests that at least two separate classes of infinitives are to be noted among the infinitive types which occur cross-dialectally, and that these two classes reflect chronologically distinct occurrences in the history of IE infinitival development. This distinction is most clearly demonstrable in Vedic, but parallel evidence exists in several other dialects.
Robert J. Jeffers (Sat,) studied this question.