APA

Markou A., Arroyo M. & Everitt B. J. (19990624). Effects of contingent and non-contingent cocaine on drug-seeking behavior measured using a second-order schedule of cocaine reinforcement in rats. : Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology.

Chicago

Markou A, Arroyo M and Everitt B J. 19990624. Effects of contingent and non-contingent cocaine on drug-seeking behavior measured using a second-order schedule of cocaine reinforcement in rats. : Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology.

Harvard

Markou A., Arroyo M. and Everitt B. J. (19990624). Effects of contingent and non-contingent cocaine on drug-seeking behavior measured using a second-order schedule of cocaine reinforcement in rats. : Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology.

MLA

Markou A, Arroyo M and Everitt B J. Effects of contingent and non-contingent cocaine on drug-seeking behavior measured using a second-order schedule of cocaine reinforcement in rats. : Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology. 19990624.