APA

Walker E., . (2000). Grammar Practice for Pre-Intermediate Students. S.l: Longman.

Chicago

Walker Elaine, . 2000. Grammar Practice for Pre-Intermediate Students. S.l: Longman.

Harvard

Walker E., . (2000). Grammar Practice for Pre-Intermediate Students. S.l: Longman.

MLA

Walker Elaine, . Grammar Practice for Pre-Intermediate Students. S.l: Longman. 2000.