. . . . . . . . . . . . . . . . . . . "Note on the crystalline electric field in nickel ammonium sulphate" . "Crystalline electric field in nickel ammonium sulphate" . "Note on the crystalline electric field in nickel ammonium sulphate"@en . "Crystalline electric field in nickel ammonium sulphate"@en . . . . .