Below you will find a complete set of details for 2 different references / citations that are related to the computation of the PDF (probability density function) for the chi-square distribution.

Reference for Citing the Online Calculator

- Soper DS. Chi-Square Distribution Probability Density Function (PDF) Calculator [Online Software]. Available from https://www.analyticscalculators.com. 2021.

Reference from the Scientific Literature

- Abramowitz M, Stegun IA. Handbook of mathematical functions: with formulas, graphs, and mathematical tables. Courier Corporation; 1964.