Bishop, D.W.; Thomas, P.S.; Ray, A.S. (1998). "Raman spectra of nickel(II) sulfide". Materials Research Bulletin. 33 (9): 1303. doi:10.1016/S0025-5408(98)00121-4.
dx.doi.org
leading reference can be found in: Shabnam Virji, Richard B. Kaner, Bruce H. Weiller "Direct Electrical Measurement of the Conversion of Metal Acetates to Metal Sulfides by Hydrogen Sulfide" Inorg. Chem., 2006, 45 (26), pp 10467–10471.doi:10.1021/ic0607585
