Cita APA (7a ed.)

Walker, E., & Elseorth, S. (1994). Grammar practice for elemementary students: [with answer key]. Longman.

Cita Chicago Style (17a ed.)

Walker, Elaine, y Steve Elseorth. Grammar Practice for Elemementary Students: [with Answer Key]. Essex: Longman, 1994.

Cita MLA (9a ed.)

Walker, Elaine, y Steve Elseorth. Grammar Practice for Elemementary Students: [with Answer Key]. Longman, 1994.