The possible covalent nature of N-H...O hydrogen bonds in formamide dimer and related systems: an ab initio study.
Grabowski SJ, Sokalski WA, Leszczynski J. The possible covalent nature of N-H...O hydrogen bonds in formamide dimer and related systems: an ab initio study. J Phys Chem A. 2006 Apr 13; 110(14):4772-9.