https://katalog.hfmdd.de/Record/ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMjMwNy8zNTg2Nzcw Cortese, Giuseppina:
From Receptive to Productive in Post-Intermediate EFL Classes: A Pedagogical Experiment. 1985. — 7.