Watkins, Calvert. 1962. Indo-European origins of the Celtic verb: I. The sigmatic aorist. Dublin: The Dublin institute for Advanced Study.
@book{jacquesestimative-watkins62celtic,
author = {Watkins, Calvert},
publisher = {Dublin: The Dublin institute for Advanced Study},
title = {Indo-European origins of the Celtic verb: I. The sigmatic aorist},
year = {1962}
}