Hello,
Thank you for inquiring about how to cite our work. It depends a bit on which values you are using and how you are applying them, but you can find the relevant list of publications here:
By default, the latest one (Beber et al. 2021) should suffice.
For future reference, you can also find this list by going to "Docs > Cite Us" on the eQuilibrator website.
Best,
Elad