APA

Allen M., Halsey M., . (1999). Twice as Nice. USA: Creative Teaching Press.

Chicago

Allen Margaret, Halsey Megan, . 1999. Twice as Nice. USA: Creative Teaching Press.

Harvard

Allen M., Halsey M., . (1999). Twice as Nice. USA: Creative Teaching Press.

MLA

Allen Margaret, Halsey Megan, . Twice as Nice. USA: Creative Teaching Press. 1999.