Anderson IM, Jones S, Twiss J. Do negative cognitive style and personality predict depression symptoms and functional outcomes in severe bipolar and unipolar disorders? Int J Cogn Ther. 2009 Dec 15;2(4):343-53. doi: 10.1521/ijct.2009.2.4.343
Phanikumar CV, Maitra B. Willingness-to-pay and preference heterogeneity for rural bus attributes. J Transp Eng A-Syst. 2007 Jan;133(1).