@book {Camacho2013, title = {Null Subjects}, series = {Cambridge studies in linguistics}, number = {137}, year = {2013}, note = {
Introduction --
The null subject parameter: introduction --
The core content of the null subject parameter --
The nature of the extended projection principle and the null subject parameter --
Identification and morphology --
Discourse identification --
Null/overt subject contrasts --
The status of preverbal subjects in null subject languages --
Parametrization, learnability and acquisition.