Em lại nhờ bác down hộ em bài này nữa ạ:
1.
http://ieeexplore.ieee.org/search/fr...d%3DSearch+All
This paper appears in: Spectrum, IEEE
Issue Date : Feb 1998
Volume : 35 , Issue:2
On page(s): 35 - 42
ISSN : 0018-9235
INSPEC Accession Number: 5852499
Digital Object Identifier : 10.1109/6.648673
Date of Current Version : 06 August 2002
Sponsored by : IEEE
thanks bác.