APA   Click to copy
Forbus, K. D., & Gentner, D. (1989). Causal reasoning about quantities.

Chicago/Turabian   Click to copy
Forbus, Kenneth D., and D. Gentner. “Causal Reasoning about Quantities” (1989).

MLA   Click to copy
Forbus, Kenneth D., and D. Gentner. Causal Reasoning about Quantities. 1989.

@article{kenneth1989a,
  title = {Causal reasoning about quantities},
  year = {1989},
  author = {Forbus, Kenneth D. and Gentner, D.}
}