APA

Pressman M. R., Pressman M. R. & Orr W. C. (1997). Understanding sleep: the evaluation and treatment of sleep disorders. Washington, D.C: American Psychological Assoc.

Chicago

Pressman Mark R, Pressman Mark R and Orr William C. 1997. Understanding sleep: the evaluation and treatment of sleep disorders. Washington, D.C: American Psychological Assoc.

Harvard

Pressman M. R., Pressman M. R. and Orr W. C. (1997). Understanding sleep: the evaluation and treatment of sleep disorders. Washington, D.C: American Psychological Assoc.

MLA

Pressman Mark R, Pressman Mark R and Orr William C. Understanding sleep: the evaluation and treatment of sleep disorders. Washington, D.C: American Psychological Assoc. 1997.