In EI login number, 1-4 digits represent the year, 5-6 digits represent the week of this year, and 7-8 digits represent the category.

For example, the access number is 200937 1230079 1.

2009 is 2009.

37 is the 37th week, that is, August when this paper entered the EI database.

12 stands for category, for example, computer is 10.

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