pKa calculation for monoprotonated bipiperidine, bimorpholine and their derivates in H2O and MeCNUudsemaa, Merle; Kanger, Tõnis; Lopp, Margus; Tamm, ToomasChemical physics letters2010 / p. 83-86 https://www.sciencedirect.com/science/article/pii/S000926140901519X