Paddock, Harold. “Simultaneously Variable and Fixed? The Status of Some Initial Sibilants in English and Proto-Indo-European”. Papers from the Annual Meetings of the Atlantic Provinces Linguistic Association (PAMAPLA) / ACTES DES COLLOQUES ANNUELS DE L’ASSOCIATION DE LINGUISTIQUE DES PROVINCES ATLANTIQUES (ACAALPA). 9 (June 6, 1986): 100–112. Accessed May 13, 2024. https://conferences.lib.unb.ca/index.php/pamapla/article/view/458.