Influence of protonation upon the conformations of bipiperidine, bimorpholine, and their derivatesUudsemaa, Merle; Laars, Marju; Kriis, Kadri; Tamm, Toomas; Lopp, Margus; Kanger, TõnisChemical physics letters2009 / 1/3, p. 92-96https://www.sciencedirect.com/science/article/abs/pii/S0009261409001857