Alvarado Ayala, M. G., Romero Rivera, J. E., & Salazar Mucia, P. A. (2003). An analysis of the results after five years of implementation of the new educational program for teachers of english plan mined at four universities of San Salvador 1998 - 2002. San Salvador: University of El Salvador.

Alvarado Ayala, María Guadalupe, José Efraín Romero Rivera, and Pedro Antonio Salazar Mucia. An Analysis of the Results After Five Years of Implementation of the New Educational Program for Teachers of English Plan Mined At Four Universities of San Salvador 1998 - 2002. San Salvador: University of El Salvador, 2003.

Alvarado Ayala, María Guadalupe, José Efraín Romero Rivera, and Pedro Antonio Salazar Mucia. An Analysis of the Results After Five Years of Implementation of the New Educational Program for Teachers of English Plan Mined At Four Universities of San Salvador 1998 - 2002. San Salvador: University of El Salvador, 2003.