A topographically and conformationally constrained, spin-labeled,α-amino acid: crystallographic characterization in peptides. - Crisma, M.; Deschamps, J. R.; George, C.; Flippen-Anderson, J. L.; Kaptein, B.; Broxterman, Q. B.; Moretto, A.; Oancea, S.; Jost, M.; Formaggio, F.; Toniolo, C. (Journal of Peptide Research, 2005)