1. Bates , D. & Maechler , M. 2010 . lme4: Linear mixed-effects models using S4 classes . R package version 0.999375-34. Retrieved from http://CRAN.R-project.org/package=lme4
2. Callahan , S. M. , Nicol , J. , Love , T. & Swinney , D. ( 2006 ) All pronouns are not created equal: The processing and interpretation of null and overt pronouns in Spanish . Poster presented at the 20th annual CUNY conference on human sentence processing , San Diego , CA .
3. Carminati , M. N. 2002 . The processing of Italian subject pronouns . Unpublished doctoral dissertation , University of Massachusetts at Amherst .