Castillo, R. M., Menèndez Giròn, S. A., Pereira Rodrìguez, J. M., Sandoval Garcìa, M. E., Tenas de Garcìa, C. A., & Trigueros, R. d. (2015). Pronunciation activities to help intensive basic english sutdents, group 6, produce the fricative sounds /s/-/z/ at The Wester Multidisciplinary Campus of The University of El Salvador, semester I-2015. Santa Ana, El Salvador: Universidad de El Salvador.

Castillo, Rocìo Marisela, Samuel Alexander Menèndez Giròn, Jessica Marisela Pereira Rodrìguez, Mauricio Ernesto Sandoval Garcìa, Cindy Alicia Tenas de Garcìa, and Roxana de Trigueros. Pronunciation Activities to Help Intensive Basic English Sutdents, Group 6, Produce the Fricative Sounds /s/-/z/ At The Wester Multidisciplinary Campus of The University of El Salvador, Semester I-2015. Santa Ana, El Salvador: Universidad de El Salvador, 2015.

Castillo, Rocìo Marisela, et al. Pronunciation Activities to Help Intensive Basic English Sutdents, Group 6, Produce the Fricative Sounds /s/-/z/ At The Wester Multidisciplinary Campus of The University of El Salvador, Semester I-2015. Santa Ana, El Salvador: Universidad de El Salvador, 2015.