16 Current trends in the development and teaching of the four language skills. Edited by Esther Uso.-Juan, Alicia Martı.nez-Flor. – Berlin, 2006. –P. 140.
17 Current trends in the development and teaching of the four language skills. Edited by Esther Uso.-Juan, Alicia Martı.nez-Flor. – Berlin, 2006. –P. 142.
19 Current trends in the development and teaching of the four language skills. Edited by Esther Uso.-Juan, Alicia Martı.nez-Flor. – Berlin, 2006. –P. 140-145.
20 See: Current trends in the development and teaching of the four language skills. Edited by Esther Uso.-Juan, Alicia Martı.nez-Flor. – Berlin, 2006. –P. 147-150. Celce-Murcia and Olshtain 2000.