Hess R, Kuhn M, Schulz-Knappe P, Raida M, Fuchs M, Klodt J, Adermann K, Kaever V, Cetin Y, Forssmann WG. GCAP-II: isolation and characterization of the circulating form of human uroguanylin. FEBS Lett. 1995 Oct 23;374(1):34–8. doi: 10.1016/0014-5793(95)01075-p. PMID: 7589507.