L2 Fossilization: A Competence or a Performance Phenomenon - Christo, Moskovsky and Silvia, Ratcheva (The Open Communication Journal, 2014)
https://katalog.adlr.link/Record/ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMjE3NC8xODc0OTE2eDAxNDA4MDEwMDA5