1. Erragh, F., Baukhari, A., Sadel, A., and Holt, E.M., Disodium Zink Pyrophosphate and Disodium (Europium) Zink Pyrophosphate, Acta Crystallogr., Sect. C: Cryst. Struct. Commun., 1998, vol. 54, pp. 1372–1376.
2. Belharouak, I., Gravereau, P., Parent, C., Chaminade, J.P., Lebraud, E., and Le Flem, G., Crystal Structure of Na2ZnP2O7: Reinvestigation, J. Solid State Chem., 2000, vol. 152, no. 2, pp. 466–473.
3. Gabelica-Robert, M., Sur une nouvelle famille de pyrophosphates, pyroarseniates et pyrovanadates du type A 2 BX 2O7, C.R. Seances Acad. Sci., Ser. 2, 1981, vol. 293, no. 7, pp. 497–499.
4. Shepelev, Yu.F., Petrova, M.A., Novikova, A.S., and Lapshin, A.E., Crystal Structures of Na2ZnP2O7, K2ZnP2O7, and LiKZnP2O7 Phases in the M 2O-ZnO-P2O5 Glass-Forming System (M = Li, Na, and K), Fiz.Khim. Stekla, 2002, vol. 28, no. 5, pp. 451–458 [Glass Phys. Chem. (Engl. transl.), 2002, vol. 28, no. 5, pp. 317–321].
5. Shepelev, Yu.F., Lapshin, A.E., and Petrova, M.A., Crystal Structure of Sodium Potassium Zinc Diphosphate NaKZnP2O7, Zh. Strukt. Khim., 2006, vol. 47, no. 6, pp. 1109–1113 [J. Struct. Chem. (Engl. transl.), 2006, vol. 47, no. 6, pp. 1098–1102].