Thank you for taking the trouble to ask.
I assume you are already citing Bechara et al. (1994) as per the readme.
For the code, as per How to cite PsychoPy code and the demo was forked from Sue Mah’s account, a reasonable citation would be Mah, S. (2024, April 10). Iowa gambling task [Computer software]. Pavlovia. https://gitlab.pavlovia.org/demos/iowa_gambling_task