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} }