In every fact-check that we publish, the resources that we use, including the source of the fact-checked statement, are provided on that specific fact-check content's page. They are just below the end of our fact-check, and easily accessible. No membership required to see the sources.
We use open and public sources to fact-check the claims. Our primary targets for a source are official statistics. Secondary ones are trustworthy international statistical pages. And if we don't have any info from those primary and secondary sources, we search the trustworthy NGOs' reports as sources.
Our publication strategy can be found here: https://www.dogrulukpayi.com/~Degerlendirme-Kriterleri