An Introduction to English Language Teaching (Revised Impression) -John Haycraft
Introduction to English Phonetics and Phonology (Volume 1 ) – Ulrike Gut
An Introduction to English Grammar (Third Edition) – Sidney Greenbaum & Gerald Nelson
Introduction to English Linguistics – Annette Becker M. A. and Dr. Markus Bieswanger
An Introduction to English Phonology – April McMahon
An Introduction to English Sentence Structure – Andrew Radford
Use of English Part 4 with Answers (Cambridge English: First)
Reading & Use of English (Practice With Keys) – Cambridge English Advanced Examination Questions