Sourses used:
Allen, William Stannard (1992). Living English structure for schools. Harlow: Longman.
Lieu, Mark Wade (2001). Understanding and Using English Grammar. White Plains (N.Y.): Longman
Mann, Malcolm (2008). Destination C1 & C2 : grammar & vocabulary : [with answer key : suitable for the updated CAE exam]. Oxford : Macmillan
Soars, John (1996). Headway : advanced. Teacher's book. Oxford : Oxford University Press
Soars, John (2001). Headway : advanced. Student's book. Oxford : Oxford University Press
Vince, Michael (1994). Advanced language practice. Oxford : Heinemann
Lieu, Mark Wade (2001). Understanding and Using English Grammar. White Plains (N.Y.): Longman
Mann, Malcolm (2008). Destination C1 & C2 : grammar & vocabulary : [with answer key : suitable for the updated CAE exam]. Oxford : Macmillan
Soars, John (1996). Headway : advanced. Teacher's book. Oxford : Oxford University Press
Soars, John (2001). Headway : advanced. Student's book. Oxford : Oxford University Press
Vince, Michael (1994). Advanced language practice. Oxford : Heinemann