APA

Abbott P., Wardle M., . (1991). Trigonometry. : Teach Yoirself Books.

Chicago

Abbott P, Wardle M.E, . 1991. Trigonometry. : Teach Yoirself Books.

Harvard

Abbott P., Wardle M., . (1991). Trigonometry. : Teach Yoirself Books.

MLA

Abbott P, Wardle M.E, . Trigonometry. : Teach Yoirself Books. 1991.