Hill, J. W. ; Petrucci, R. H. ; McCreary, T. W. ; Perry, S. S. General Chemistry, 4th ed / O., pp45-46, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.
Hill, J. W. ; Petrucci, R. H. ; McCreary, T. W. ; Perry, S. S. General Chemistry, 4th ed / O., p5, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.