Erratum to "Lattice constellation and codes from quadratic number   fields" [IEEE Trans. Inform. Theory, vol. 47, No. 4, May. 2001]
  We correct a partial mistake for a metric presented in the article "Lattice constellation and codes from quadratic number fields" [IEEE Trans. Inform. Theory, vol. 47, No. 4, May. 2001]. We show that the metric defined in the article is not true, therefore, this brings about to destroy the encoding and decoding procedures. Also, we define a proper metric for some codes defined in the article and show that there exist some $1-$error correcting perfect codes with respect to this new metric. 
Murat G\"uzeltepe
cs.IT math.IT