Rumbaut, Massey et Bean (2006) Linguistic Life Expectancies: Immigrant Language Retention in Southern California https://papers.ssrn.com/sol3/papers.cfm?
Rumbaut (2009) A Language Graveyard? The Evolution of Language Competencies, Preferences and Use Among Young Adult Children of Immigrants https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1883184
Ortman (2009) Estimates of Intergenerational Language Shift: Surveys, Measures and Domains https://paa2009.princeton.edu/papers/90134