Segal examines the history and usage of the diacritical point from before the seventh century up to the thirteenth century, taking into account both the East and West Syriac traditions. Segal basis his studies both on analysis of manuscripts at the British Museum, as well as the grammatical works of Syriac authors. Это и многое другое вы найдете в книге The Diacritical Point and the Accents in Syriac (J. B. Segal)