1. Historical and Comparative Linguistics;Anttila,1989
2. Deutsche Syntax, Bd. IV;Behaghel,1932
3. Relations de personne dans le verbe;Benveniste;Bulletin de la Société de Linguistique,1946
4. Generality, Gradience, and the All-or-None;Bolinger,1961
5. Aspects of Language;Bolinger,1975