Leopold, W. (1949). Speech development of a bilingual child. Vol III: Grammar and general problems in the first two years. New York: AMS Press. [FULLTEXT]
A History of Psycholinguistics
Bibliography for Levelt (2013)

Leopold, W. (1949). Speech development of a bilingual child. Vol III: Grammar and general problems in the first two years. New York: AMS Press. [FULLTEXT]