This site cites three specific background sources, with its own direct note attached: none of these organizations endorses SodaPeak or this review.
The U.S. FDA's general page on dietary supplement regulation and consumer information, the FTC's Health Products Compliance Guidance, and the NIH Office of Dietary Supplements' general fact-sheet list.
Worth noting these are general regulatory-context references, not ingredient-specific citations for SodaPeak — a different citation approach than sites that link ingredient-level research, appropriate given this site's own admission that no ingredient panel is published.