TY  - BOOK
AU  - Murphy,Raymond
TI  - Essential grammar in use: a self-study reference and practice book for elementary students of English, with answers 
SN  - 9780521675802
U1  - 425 23
PY  - 2009///, c2007
CY  - Cambridge
PB  - Cambridge University Press
N1  - Incluye índice (pp. 315-319)
ER  -