1. H. Montgomery, R.V. Chastain, J.J. Natt, A.M. Witkowska, E.C. Lingafelter, The crystal structure of Tutton’s salts. VI. Vanadium(II), iron(II) and cobalt(II) ammonium sulfate hexahydrates. Acta Cryst. 22, 775–780 (1967)
2. P. Groth, Chemische Kristallographie II (Verlag W. Engelmann, Leipzig, 1908), p. 509
3. E.N. Maslen, S.C. Ridout, K.J. Watson, The structures of Tutton’s salts. I. Diammonium hexaaquamagnesium(II) sulfate. Acta Cryst. C44, 409–412 (1988)
4. T.H. Tahirov, T.H. Lu, A precise structure redetermination of nickel ammonium sulfate hexahydrate, Ni(H2O)6·2NH4·2SO4. Acta Cryst. C50, 668–669 (1994)
5. K.V. Narasimhulu, J.L. Rao, A single crystal EPR study of VO2+ ions doped in Cs2Co(SO4)2·6H2O Tutton salt. Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 53, 2605–2613 (1997)