Bishop, D.W.; Thomas, P.S.; Ray, A.S. (1998). “Raman spectra of nickel(II) sulfide”. Materials Research Bulletin33 (9): 1303. doi:10.1016/S0025-5408(98)00121-4.
Bonati, Antonio; Pisano, Gabriele; Royer Carfagni, Gianni (12 October 2018). “A statistical model for the failure of glass plates due to nickel sulfide inclusions”. Journal of the American Ceramic Society. doi:10.1111/jace.16106.
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