References :

Asher, J. (1972). Children's First Language as a Model for Second Language Learning. Modern Language Journal, 56, 3,133-139.

Asher, J., Kusudo, J., & de la Torre, R. (1974). Learning a Second Language through Commands: The Second Field Test. Modern Language Journal, 58, 24-32.

Omaggio Hadley, A. (2001). Teaching Language in Context. (3rd ed.). Boston: Thomson-Heinle.