@inbook {Deutsch2001, title = {Person in singletons, siblings, and twins}, booktitle = {Language acquisition and conceptual development}, year = {2001}, pages = {284{\textendash}315}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, address = {Cambridge}, author = {Deutsch, Werner and Wagner, A. and Burchardt, R. and Schultz, N. and Nakath, J.}, editor = {Bowerman, M. and Levinson, S. C.} } @article {1978, title = {Ihr, dir, or mir? On the acquisition of pronouns in German children}, journal = {Cognition}, volume = {6}, year = {1978}, pages = {155{\textendash}168}, author = {Deutsch, Werner and Pechmann, Thomas} }