"Incentive hope" and the nature of impulsivity in low-socioeconomic-status individuals.Walsh F, Cheries E, Kwak Y.Behav Brain Sci. 2019 Jan;42:e55. 

[Incentive program to strengthen motivation for increasing physical activity via conjoint analysis].Matsushita M, Harada K, Arao T.Nihon Koshu Eisei Zasshi. 2017;64(4):197-206.

The Effect of Varying Incentive Amounts on Physician Survey Response.Noel H, Huang AR.Eval Health Prof. 2019 Mar;42(1):71-81.-