APA

(1997). Vision - Vol.89 No.6 (1997). México: Vision Incorporated.

Chicago

1997. Vision - Vol.89 No.6 (1997). México: Vision Incorporated.

Harvard

(1997). Vision - Vol.89 No.6 (1997). México: Vision Incorporated.

MLA

Vision - Vol.89 No.6 (1997). México: Vision Incorporated. 1997.