Wu, S., Declercq, J.-P., Tinant, B., & Van Meerssche, M. (1988). Crystal-structure and Conformation of Short Linear Peptides .9. L-tyrosyl-l-tyrosyl-l-tyrosine Hemihydrochloride Trihydrate. Societes Chimiques Belges. Bulletin, 97(1), 27-32. https://doi.org/10.1002/bscb.19880970105 (Original work published 1988)