Zaragoza:

BB	Murphy, Raymond. English grammar in use : a self-study reference and practice book for intermediate students of English : with answers / Raymond Murphy . - 4th ed., Cambridge University Press, cop. 2012.
BB	Oxenden, Clive. English file : Intermediate / Clive Oxenden, Christina Latham-Koenig with Jane Hudson. 4ª ed.

Zaragoza:

BB	Murphy, Raymond. English grammar in use : a self-study reference and practice book for intermediate students of English : with answers / Raymond Murphy . - 4th ed., Cambridge University Press, cop. 2012.
BB	Oxenden, Clive. English file : Intermediate / Clive Oxenden, Christina Latham-Koenig with Jane Hudson. 4ª ed.