Bibev, D., Johansson, S., Leech, G., Conrad, S., & Finegan, E. (1999). Grammar of spoken and written English. Harlow: Pearson education limited.

Bibev, Douglas, Stig Johansson, Geoffrey Leech, Susan Conrad, and Edward Finegan. Grammar of Spoken and Written English. Harlow: Pearson education limited, 1999.

Bibev, Douglas, et al. Grammar of Spoken and Written English. Harlow: Pearson education limited, 1999.