Faculty Scholar's website linked here.
Somervell, Jacob, and D.Scott McCrickard. “Better Discount Evaluation: Illustrating How Critical Parameters Support Heuristic Creation.” Interacting with Computers, vol. 17, no. 5, Sept. 2005, pp. 592–612. EBSCOhost, https://doi.org/10.1016/j.intcom.2005.03.007.