Cambridge IGCSE: english as a second language by John Reynolds, 2014
Cambridge IGCSE: english as a second language (4th ed.)by Peter Lucantoni, 2014
Grammar for teachers: a guide to American english for native and non-native speakers (2nd ed.)by Andre DeCapua, 2017
Teaching english as a second or foreign language by Marianne Celce-Murcia et. al
