Grammar reference:

Oxford Grammar for EAP Paterson, K. & R. Wedge; Oxford University Press

English Grammar in Use Murphy, R.; Cambridge University Press

Practical English Usage Swan, M.; Oxford University Press

A Practical English Grammar Thomson, A.J. and Martinet, A.V.; OUP

Advanced Grammar in Use Hewings, M.; CUP

Advanced English Practice Graver, B.D.; OUP

 

Dictionaries:

http://www.oxfordlearnersdictionaries.com

http://dictionary.reference.com/

http://oxforddictionary.so8848.com