Cita APA (7a ed.)

Clarke, D. S. (2003). Sign levels: Language and its evolutionary antecedents. Kluwer Academic Publishers.

Cita Chicago Style (17a ed.)

Clarke, D. S. Sign Levels: Language and Its Evolutionary Antecedents. Dordrecht, The Netherlands ; Boston: Kluwer Academic Publishers, 2003.

Cita MLA (9a ed.)

Clarke, D. S. Sign Levels: Language and Its Evolutionary Antecedents. Kluwer Academic Publishers, 2003.