Desmond, HP., Pauwels, S., & Dockray, GJ. (1986). Heterogeneity of Progastrin in Human Antrum and Gastrinoma - Isolation of a 2nd Peptide Related To the Gastrin Precursor. Regulatory Peptides, 15(2), 171. https://doi.org/10.1016/0167-0115(86)90099-6 (Original work published 1986)