APA
Christensen I. P., Christensen I. P. & Wagner H. L. (2001). Psychology. New Delhi: Viva Books.
Chicago
Christensen I P, Christensen I P and Wagner H L. 2001. Psychology. New Delhi: Viva Books.
Harvard
Christensen I. P., Christensen I. P. and Wagner H. L. (2001). Psychology. New Delhi: Viva Books.
MLA
Christensen I P, Christensen I P and Wagner H L. Psychology. New Delhi: Viva Books. 2001.