1. Chapter 10. Syntactic attrition in L2 Japanese missionary language
2. Engstler, C. (2012). Language retention and improvement after a study abroad experience [Ph.D. dissertation]. Northwestern University. https://linguistics.northwestern.edu/documents/dissertations/linguistics-research-graduate-dissertations-engstlerdissertation2012.pdf.
3. Mehotcheva, T. M. (2010). After the Fiesta is over. Foreign language attrition of Spanish in Dutch and German Erasmus students [Ph.D. dissertation]. University of Groningen. https://pure.rug.nl/ws/portalfiles/portal/14493330/13_thesis.pdf.