1. Kwisda, K., Cantz, T. & Hoppe, N. Nat. Biotechnol. 39, 796–798 (2021).
2. US Food & Drug Administration. Xenotransplantation guidances. https://www.fda.gov/vaccines-blood-biologics/biologics-guidances/xenotransplantation-guidances (2016).
3. US Food & Drug Administration. FDA staff manual guides, volume IV - agency program directives. Combination products: intercenter coordination of regulatory activities for genetically engineered animals and their expression products. https://www.fda.gov/media/92780/download (2015).
4. 21 CFR 514.
5. 21 CFR 312.